Skip to main content
search
0
All Posts By

GEARSTAR PERFORMANCE

In Transmission & Drivetrain

GM 4L80-E Transmission Swap Tips and Tricks

GM 4L80-E Transmission Swap Tips and Tricks - Gearstar Performance Transmissions

GM 4L80-E transmission swap tips are needful for anyone looking to revamp the performance of their transmission. The same goes if your ride is used for off-road and racing applications. These tips are from car enthusiasts and lovers of vehicles that can handle the high load that will be thrown at it.

Therefore, you’ll be relying on the most important tips and tricks out there, instead of trying just about anything on your transmission. In the end, the level of performance you’ll get will be more than impressive. With that in mind, here are some of our tried-and-true tips and tricks for swapping GM 4L80-E transmissions that you can try today.
–

GM 4L80-E Transmission Fluid Levels

If you’ve dedicated the time, money, and energy to your GM 4L80-E transmission swap, it is useful to ensure you have enough oil in it. How can you do that? It’s by using the correct dipstick measurement given that some of these units may not measure the right oil level.

Accordingly, if the measurement reads ‘full’, the dipstick has to be level with the pan rail. This is the case’s flat part where the pan bolts. Therefore, you can take this measurement with the dipstick mounted in the car. Here, you could get the transmission in and bolted to the cross member.

The next step is to drop the pan and assess the stick. Mark a new line on the stick if the right measurement was not gotten correctly. Now you’ll agree that this is an easier process that can save you from damaging your transmission in the long run.
–

Automatic Transmission Accumulators

It’s possible to block the third or fourth accumulators using a wide range of options. An option is to purchase an accumulator delete plate that will offer high-level performance.

This plate is also not so pricey and it comes with the promise of excellent performance each time. Another option is to resort to the stock accumulator housing and block the feed holes. This blockage can be done with the help of a set screw such as a 5/16″-18 tap and set screw.

It’s worth pointing out that the bore that lacks the pin is for the third accumulator whereas the hole that comes with the pin is for the 4th. Coupled with that, the 2nd accumulator is the case and there’s no need to block it.
–

GM 4L80-E Transmission Pressure Booster

The GM 4L80-E transmission pressure can be increased using a boost valve. In this case, if you’re getting less than 1khp to the tire, it’s useful to use a valve and sleeve while maintaining the stock pressure regulator spring. Contrastingly, you need to resort to the sonnax spring if the transmission is making over  1khp.
–

Transmission Snap Ring Enhancement

There’s another enhancement you can carry out and that is the improvement of the intermediate clutch snap ring. Although there is a stock ring, the latter may be too weak to handle the performance required.

Accordingly, settle for a snap ring from a TorqueFlite 727. since it has a level of thickness that will impact positively on your ride. Also, if the clearance is overly tight with the .106, you can opt for a thickness option of .088.
–

GM 4L80-E Transmission Valve Body Separator Plates

You could take the extra step to drill the plate separator since it can also up performance. Here, the 5/64″ (.078) is suited for lighter cars and even lower power units for 2nd gear. Also, the 3/32 (.093) is ideal for the heavy vehicles around 4k+ lbs.

The 3rd can be fixed in the 7/64 (.110), which is suited for most vehicles, When it comes high hp/heavy, you can resort to 1/8″ (.125) and the same can be said for the 4th. Needless to say, these numbers may vary from one car to the other.

On the other hand, it is worth pointing out that a bigger hole may result in firmer and faster shifts. And if the accumulators have been blocked, it’s ideal to settle for the smaller hole options since shifts will be faster and firmer due to the block on accumulators.

Once that is done, you should also consider replacing the electronics and harness. It’ll not cost an arm and a leg to get this replacement down and you can even replace the EPC solenoid. The latter is useful in controlling GM 4L80-E transmission pressure.
–

GM 4L80-E TransGo HD2 Kit

The TransGo HD2 Kit may not be the most ideal part to resort to. This is because it dual feeds the direct clutch while also increasing the line pressure. Also, the direct clutch is useful in the reverse gear and the third gear.

Coupled with that, there are two chambers in the apply piston for this clutch. And in the reverse gear, both chambers are used and it’s able to get full apply force. But when it comes to the 3rd gear, only one chamber is used, which helps in reducing the apply area and the holding power.

That being the case, dual feeding the clutch will enable the chambers of the apply piston to also resort to the 3rd gear. On the other hand, if you plan on removing the center lip seal of the apply piston, it may be needful to remove the 2nd sealing ring on the center support.

You may also have to connect the case passage with a 3/8 cup plug in. Likewise, you could tap the center support and install a set screw. And while at it, ensure that the set screw is linked below flush to prevent the non-sealing against the case.
–

The Bottom Line

Relying on the GM 4L80-E transmission swap tips and tricks above can help you create a transmission that will handle all the load posed at it. These tips can serve you anytime, whether you’re using a new or old transmission. The goal is to ensure you end up with a ride whose performance is impressive. Now if that’s what you’re out to get, try these tips.

In Transmission & Drivetrain

TH350 Transmission Identification, Decoding and Super-Tuning

TH350 Transmission Identification, Decoding and Super-Tuning - Gearstar Performance Transmissions

The TH350 (Turbo-Hydramatic) transmission identification, decoding, and super-tuning are what sets it apart from other transmissions. Its identification, for instance, helps you to differentiate this one-piece unit from other transmissions launched by General Motors.

And the super-tuning of this unit ensures that you can improve its performance to be a ride worth taking on fast and hard spins. Now this and many more are what we’ve outlined below. Therefore, work with us let’s show you all you need to know about this unit.

TH350 Transmissions 101

The TH350 transmission is a three-speed automatic transmission launched by General Motors in vehicles from 1968. It can also be said this model was created as a collaboration between Chevrolet and Buick, where the transmission was made to be compact, strong, and versatile.

On the other hand, the TH350 was to serve as a replacement to the Powerglide transmission, which is a two-speed automatic transmission. Cars that used the TH350 transmission include those from the late 1960s, as well as some GM all rear-wheel-drive vehicles launched in 1984.

The transmission model was used in these cars until the early 1980s when the 700R4 transmission was launched. That being said, chances that you’re using a GM vehicle with the TH350 transmission are high if the car is a model launched around these years.

TH350 Transmission Identification

The TH350 transmission is 21-3/4″ long and its body is made of aluminum alloy. The unit comes with a bell housing and weighs 120 lbs. Here is a list of steps that will help you to identify the TH350 transmission:

1. Set Up the Wheel Chocks

Adjust the wheel chocks at the back of the tires to ensure that the vehicle is firmly rooted to the ground. Use your jack to lift the vehicle slightly while also ensuring that the jack sits securely beneath the frame rails.

You can then lower the car onto the stands. Slide beneath the vehicle and find the transmission. This transmission is mostly stationed at the rear-wheel of cars hence, its location may be the same in yours.

2. Count the Number of Bolts

Ascertain the number of bolts that are secured to the transmission oil pan. And if the number of bolts is around 13, then it means the unit is either a TH350 or TH400. On the other hand, the transmission oil pan is usually bolted to the transmission bottom.

However, you can tell if it is a TH350 or TH400 depending on the transmission oil pan’s shape. If the pan is square in shape and looks five-sided due to a cut in one corner, then you are dealing with the TH350.

3. Check the Length of the Transmission

It is also important to measure the length of the transmission. This measurement should be taken from the front and from where it bolts to the back of the engine to the transmission’s end that links the tailshaft housing.

On the other hand, there’s no need to measure the tailshaft housing and this is an adapter with a cone-shape design. It is worth noting that the length may range from 22 ¼ to 22 ¾ inches if it is the TH350 transmission.

4. Find the Vacuum Modulator

The next step is to find the vacuum modulator. This modulator has been stationed at the transmission’s side and there may be a rubber vacuum line connected to it. You’ll know it’s the TH350 if you have the fitting attached to the right frontal side of the transmission. However, it is the TH400 if this fitting is at the transmission’s front-rear side.

5. Check the Connection

There’s a cable that may be connected to the transmission’s side and next to the location of the shifter linkage. In this case, you are to ascertain if the cable is connected to the engine. The cable is a kick-down cable and the TH350 has this cable whereas the TH400 does not have this feature.

TH350 Decoding

One more thing you can fall back on to identify the TH350 is the stampings placed on the transmission’s side. The part codes that may be evident include the M33, M38 & M39 and these codes were for the conventional TH350.

On the contrary, the TH350C, a variant of the TH350 that has a lock-up torque converter had codes including MV4, MX2, MX3 & MX5. Asides from this, other variants of the TH350 were launched and these are the TH200, TH200C, TH250, TH250C and TH375.

TH350 Super-Tuning

Super-tuning the TH350 transmission involves modifying the stock transmission to ensure it is suited for street or strip use. The stock transmission may be able to withstand the impact but only to a certain degree, which brings about the need for super tuning to handle high-performance applications.

And using this transmission comes with an advantage since many car enthusiasts believe that out of all GM transmissions, it is the budget high-performance automatic ride. Therefore, you can carry out inexpensive changes to this transmission even without taking it out of the car. Here’s what you need to begin:

1. Modifications to Certain Components

Changes in components like the governor alterations, valve body recalibration, and modulator swaps can improve the TH350 transmission. By improvement, you can expect enhanced shift timing. These modifications can be made without removing the transmission from the car.

2. Upgrades

Specific upgrades are needed if your transmission will be used in applications that transmit 400 lbs-ft of torque or higher through the transmission. The limit will be dependent on the vehicle’s gear ratio, weight, driving style, and even traction.

3. Other Minor Upgrades

A TH350 rebuilt is not complete unless you have a high-performance clutches and even reducing the friction. This setup will enable the transmission to send more power to the wheels, which could also increase durability.

And if you’re wondering how you’ll reduce the unit’s friction, you can start by using needle roller bearings. These bearings can be used at the front planetary pinion carrier as well as the rear planetary ring gear.

The Bottom Line

Now that you know the TH350 transmission identification, decoding, and super-tuning, you have a better knowledge of your transmission. In the same vein, you’re well informed on how to improve it to be more durable and handle street racing. And given that this is a transmission that has stood the test of time, its rebuild will yield even more impressive results.

In Transmission & Drivetrain

How to Update Your Vehicle’s Transmission Systems to Factory Specifications

Automatic-Transmission-Rebuild-Kits

An efficient transmission system is essential for the smooth functioning of any vehicle. When you start experiencing unusual sounds, odd odors, delayed movements, or fluid leaks in your car, it is the right time to go for quick repair service. In such scenarios, users can either replace their transmission systems or rebuild it with the help of specialized kits.

Rebuilding a transmission system is always a better option than replacing it entirely. There is no point in getting the entire system changed when you can get the damaged parts fixed at a much lower price. Once the system has been taken apart, any damaged component present inside can be quickly replaced. For a durable rebuilding, the following components are essential:

Soft Parts

This comprises all the transmission parts that wear out easily and degrade the overall efficiency of the system. A master rebuilding kit consists of spare clutches, bands, seals, gaskets, bushings, bearings, and sealing rings for replacing the damaged ones.

Hard Parts

This includes additional hardware components including solenoids and transmission cases that are essential for completely upgrading a transmission system. It is better to opt for automatic transmission rebuild kits that come with these components to avoid added expenses.

Transmission Fluid

High-quality transmission fluids are essential for thorough cleaning of the system. These fluids are vehicle-specific and should be used only if they comply with the technical specifications of the manufacturer.

Gearstar Performance Transmissions is a dedicated supplier of high-performance automatic transmissions built by skilled technicians. If you want to buy automatic transmission rebuild kits, Gearstar Performance Transmissions is a good way to go.

In Transmission & Drivetrain

What Is a Lockup Torque Converter?

What Is a Lockup Torque Converter? - Gearstar Performance Transmissions

Have you ever wondered what a lockup torque converter, or when should a torque converter lockup? If you have, then let’s explain each of these to you, and generally, all you need to know about a torque converter. But first off, you already get the picture that this is a major component in your car. And that being so, its function aid the car’s performance.

Understanding Torque Converters

A torque converter is a coupling that sends rotating power to a rotating driven load. This power moves from the prime mover such as an internal combustion engine before it gets to the load. It can, therefore, be said that the torque converter creates a connection between the power source and the load in an automatic transmission.

This component is also connected to the flexplate directly, and the latter connects directly to the crankshaft. A torque converter has the major characteristic of multiplying torque if the output rotational speed is low. And this multiplication enables the fluid from the turbine’s curved vanes to deflect off the stator.

The early designs of the torque converter caused an RPM slippage of fluid between its turbine and impeller. When that happens, there is often a disturbance in the oil and this turbulence leads to the generation of heat. Automakers began to use air vanes positioned outside the torque converter in a bid to reduce the heat and cool the oil.

Nonetheless, this structure was used in small vehicles and it showed very little success. The oil was moved through the transmission cooler just to reduce the heat, but at the expense of energy and fuel being wasted.

What Is a Lockup Torque Converter?

Lockup torque converters are a type of converter that has a clutch. The engagement of this clutch causes the engine to lock to the transmission input shaft thereby leading to a direct 1:1 drive ratio. A lockup torque converter is used since it offers fuel economy, enabling you to use fuel minimally while on that joy ride.

History of Lockup Converters

Lockup torque converters gained popularity when it was discovered that manual transmissions are more fuel-efficient than automatic transmissions. The old torque converters also led to a loss in RPM between the gearbox’s crankshaft and input shaft. For this reason, it earned automatics the name slushbox at the time.

On the other hand, car manufacturers had to meet fuel economy targets set by the government. Accordingly, automatic transmissions were made to have an overdrive which helps to improve fuel economy. And this overdrive enabled the engine to turn while in lower RPM as the vehicle accelerates at a fast speed.

While this was an advantage, it wasn’t all so rosy when the engine turned slowly given that there was a slippage of the torque converter. As the torque converter slipped, it generated heat, which could potentially affect the converter and transmission negatively.

This heat also impacted on fuel economy, thereby overriding the purpose the overdrive was used in the first place. Accordingly, a lock-up of the converter helped to curb this slippage, and at the same time reduce heat and improve fuel economy.

Stages of Operation

The operation of the lockup converter is a bit complicated but one can still gain an understanding of it. In this case, there is a lock of the turbine to the torque converter’s case by the hydraulic pressure and this occurs when the crankshaft and input shaft are to turn at the same time while driving.

The engagement of the lockup clutch causes the fluid in the converter to rotate and at a speed similar to other components of the converter. The good thing is, heat is curbed significantly and so is the oil turbulence. The movement of the fluid can be attributed to the circulation which cycles the fluid through the cooler.

Furthermore, the lock-up mechanism takes advantage of a frictional clutch which is managed by a hydraulic pressure circuit. The engagement of the mechanism causes the components of the torque converter to serve as a rotating flywheel mass. As a result, this helps to reduce the load on the radiator while promoting fuel economy.

Lockup Torque Converter Failures

A torque converter lockup clutch may fail and there are different ways this failure can occur. For instance, this component can remain locked up, and as such, it causes the engine to stall as the car is braked. Another way it can fail is if the component does not lock and that results in increased fuel consumption as well as radiator temperature.

Finally, the converter can tend to slip when it is engaged, thereby allowing the engine speed to increase at a constant speed. It is worth noting that a torque converter may not lockup for the following reasons:

    • A cold engine temperature: There are cases where the converter may not lockup except the coolant temperature reaches 120°F.
    • Lockout of the overdrive unit: An overdrive unit that is locked-up causes the torque converter lockup to also be locked out.

Signs of a Failing Torque Converter

There are times when your lockup clutch will not engage, and you can easily spot out when that happens. To this, you need to pay attention to the transmission shift timing and quality. You can also use an auxiliary tachometer since there are cases where the lockup clutch engagement may be gentle with a minor change of engine speed.

On the other hand, torque converters will tend to unlock from the application of the brake or at the release of the throttle. The disengagement of the clutch may be easier to spot out compared to the engagement, given that it occurs gradually in some cars.

The Bottom Line

A lockup torque converter is important in automatic transmissions to reduce slippage. And once slippage is curbed, heat generation is minimal while fuel economy is improved. This and many more have been outlined above to give you an insight into this component and why you may need one.

In Transmission & Drivetrain

Upgrading Your Ford C6 Transmission for Modern Toughness

Upgrading Your Ford C6 Transmission for Modern Toughness - Gearstar Performance Transmissions

You can upgrade your Ford C6 transmission to ensure it can meet the modern-day expectation of performance and toughness. This may be a classic ride, but the mere fact that it was built to offer long term durability means it can be revamped to handle whatever you throw at it. To think that this transmission was once built for the most powerful Ford engines back in the 1970s and specifically high-performance sedans and Mustangs, a lot can be expected after its rebuild.

Therefore, the outcome is quite promising since you already have something solid to work with. You only need to find the best parts out there that can take this transmission’s performance one step further to ensure you get the best horsepower. Read on and we’ll show you how to make your C6 transmission rugged enough to offer more impressive performance.

Overview of the Ford C6 Transmission

For the uninitiated, the Ford C6 was designed by Ford Motor Company and it was prevalent between 1966 and 1996. This is a heavy-duty three-speed automatic transmission and upon its launch, Ford marketed it as the SelectShift Cruise-O-Matic.

The Ford C6 featured a less complex build, lighter weight, greater torque capacity, and less power loss compared to its predecessor, the MX transmission. These capabilities were achieved without a larger build compared to the design of its predecessor.

Interestingly, the C6 was also the first automatic transmission built to be compatible with the Borg-Warner flexible shift band in a bid to improve its service life and durability. Cars that used the C6 transmission include the:

    • 1978–1991 Ford Bronco
    • 1967–1996 Ford F-Series
    • 1964–1970 Ford Fairlane
    • 1966-1974 Ford Galaxie
    • 1966–1980 Ford LTD
    • 1977–1979 Ford LTD II
    • 1966–1979 Ford Ranchero
    • 1966–1979 Ford Thunderbird
    • 1968–1976 Ford Torino
    • 1966–1979 Lincoln
    • 1966–1969 Mercury Comet
    • 1967–1973 Ford Mustang
    • 1967–1978 Mercury Cougar
    • 1966–1972 Mercury Meteor
    • 1968–1976 Mercury Montego
    • 1968–1974 Mercury Monterey
    • 1977 Mustang Cobra 2

Accordingly, if your ride falls among this list, let’s show you how to upgrade your C6 transmission to handle the challenges it’ll face while gliding on a modern road. It may be a transmission used in classic cars, but it can still be a ride you’ll enjoy cruising around town.

How to Upgrade Your Ford C6 Transmission

You can try the following to beef up the performance of your C6 transmission:

1. Custom Parts

The C6 transmission boasts of being lighter than the MX transmission, however, it still has a lot of weight when it is not compared side-by-side with its predecessor. The effect of this heavyweight is seen in the loss of horsepower as parts and pieces of the transmission try to turn.

On the other hand, combining custom parts with certain C6 components can help to reduce the loss of horsepower. In line with that, a modern 4R100 electronic-overdrive can also be paired with this mix to ensure the transmission can withstand high impacts it will be susceptible to.

2. Valve Body Upgrades

The valve body of your C6 transmission can also be upgraded to enable automatic shifting. A valve body shift kit also comes with the promise of giving firmer shifts and can eliminate problems such as band failure, clutch chatter, and premature clutch.

And while at it, a trans-brake can be installed which will be most appreciated if you’re a drag racer. Another consideration is the use of thicker high-performance bands or optionally settling for a deeper oil pan.

3. Bell Housings

The stock case can be mounted with an SFI-certified bell housing, which could push the horsepower even further. If you’ll like a clearer picture of what to expect, then that horsepower may be around 1,000 hp, 2,000 hp, or more.

4. C6 Planetary Carriers

Switching to C6 planetary carriers that are stronger can also improve the performance of your transmission. Here, the new planetaries can surge the transmission’s horsepower to over 2000 hp, and the latter can be expected if a change has been made to the input shaft.

What’s more, the clutch packs can provide better surface material as well as more clutches to support greater gripping power. Needle bearings are also used to replace thrust bearings in several of the rolling components to reduce friction.

5. First and Reverse Planetary Gearset

There is a three or four pinion unit in the First and Reverse planetary gearset. This unit is made of aluminum and it can be replaced with a six-pinion planetary gearset that is made of steel. An increase in the number of pinions aids in the distribution of load and the change in the material makes the unit stronger.

6. Lincoln Drum

A Lincoln drum can be used in this transmission. This drum has higher snap-ring groove and as such, it can support the installation of more clutches. While the stock Lincoln drum may feature four clutches, up to six clutches can be fitted in it to offer a higher level of grip.

7. Aftermarket Clutches

There are less thicker aftermarket clutches you can rely on instead of the stock clutches. Let’s take for instance a clutch that is 0.0065-inch-thick instead of the stock clutches that is 0.0080-thick. Choosing less thick clutches provides space for stacking.

8. Gear Ratios

The C6 transmission comes with First, Second, and Third gear ratios that are 2.40:1, 1.40:1, and 1:1 respectively. Nonetheless, a wide-ratio gearset can be used to provide a First gear ratio that is numerically larger.

The result will be 2.72:1 and 1.54:1 for the first gear and second gear, respectively. Opting for a higher first gear ratio would be especially beneficial if you have a heavy car,  which makes the gear act faster and there’s no increase in the driving RPM.

The Bottom Line

These are the tips you can use to upgrade your Ford C6 transmission and give it that level of performance you believe it can achieve. What’s more, you get to know about the transmission you’re using and why it is a good choice for an upgrade of this type. For starters, it was built with the intention to be tough hence the foundation was set already.

Nonetheless, you can fall back on the expertise of a professional to help you out if you’re uncertain about how to carry out these upgrades yourself. Give or take, you’ll spend a few hundred bucks in a transmission repair shop, which will save you from ruining your transmission while on a quest to experiment.

In Transmission & Drivetrain

Upping the Performance of Your 700R4 Rebuild

Upping the Performance of Your 700R4 Rebuild - Gearstar Performance Transmissions

Improving the performance of your 700R4 rebuild comes with a basket-full of benefits. For starters…

An upgrade will make your transmission powerful enough to handle drag racing, while at the same time offering an enjoyable driving experience around town. This is because there will be minimal or nonexistent sluggishness in shifts to impact on power.

On the other hand, it’s worth noting that you have the choice of changing the transmission entirely. But we all know how expensive a change can be, hence, upping the performance is a cheaper alternative to getting a more enhanced performance.

Therefore, if you have a 700R4 rebuild and you’re ready to give it a boost that will result in high-level performance, work with us and we’ll show you how to get started. But get this first!
–

Modern vs. Automatic Transmissions

Unarguably, modern overdrive transmissions are controlled by computers, which differs from older automatics like the 700R4 that rely on a valve body to be mechanically controlled. It, therefore, follows that a change in certain parts of the valve body can improve its performance. It’ll be able to provide firmer shifts, while at the same time-saving power.

Accordingly, one major part of the 700R4 valve body you’ll want to focus on is its TV cable, since this transmission may be damaged as a result of a poorly adjusted TV cable. The TV cable helps in adjusting the internal line pressure as well as part throttle shifting

A TCI Automotive Constant Pressure Valve Body kit can help you to work on the TV cable. What the TCI system does is to add parts that will maintain the accurate line pressure every time, and this means there’s no need to struggle in making a perfect adjustment to the TV cable.

Another kit that may prove useful is a lockup wiring kit. This kit offers two possible options where you can either lockup the converter manually whenever you want, or lockup the converter while in Fourth gear, automatically. Now pair these kits with a powerful torque converter and you’ll be able to turn even the most sluggish 700R4 rebuild into a faster and more powerful transmission.
–

Boosting the Performance of Your 700R4 Rebuild

Here are the simple steps that will help you to improve the performance of your 700R4 rebuild:

1. Take Off the Pan and Filter

You need to take off the pan on the 700R4 to expose the large flat filter beneath it. You can then proceed to remove the filter and its seal before disposing of both. Once the filter is off, you’ll be presented with the valve body. This component controls the shifting of the transmission.

2. Remove the 1-2 Accumulator

Take off the 1-2 accumulator by unloosening the bolts that secure it in place. These bolts are to be separated from others since they are unique to the accumulator.

3. Remove the Auxiliary Valve Body

The next step is to take out the auxiliary valve body while ensuring that the stock check valve is not lost because you’ll still have a need for it.

4. Unbolt and Remove the Throttle Pressure Mechanism

Proceed to unbolt the throttle pressure mechanism and then remove the component. Also, the wire cable linkage should be disconnected as the mechanism is pulled up and the bolt securing the detent roller spring assembly is disengaged.

5. Remove the Valve Body Bolts

Any leftover valve body bolts can now be removed. Next, the valve body, gasket, and separator plate can be taken off of the transmission. This will also enable you to remove the 3-4 accumulator piston and piston pin.

Both of these are situated beneath the region where the 1-2 accumulator was taken out of. And worthy of note, is to pay attention to the balls in the valve body, which may fall out in case you don’t have spares to serve as a replacement during reassembly.

6. Remove the Pressure Regulator

The transmission pump has a pressure regulator, and this component needs to be removed as well. Here, apply pressure downwards on the TV boost valve sleeve and use snap ring pliers to remove the retaining ring. Proceed to remove the TV boost valve sleeve, valve, and the reverse boost sleeve. What you’ll have is the top rows parts coming out where the lower row features the TCI parts.

7. Choose Spring Type

You can either use a silver spring to have a firm-style shift or attach the shim to the silver spring to get a street/strip-style shift. Another spring option is a gold spring without the shim and this offers hard shifts.

After the disassembly, you’ll notice some check balls from the stock valve body. These are reusable 1/4-inch silver ones that are four in number. There’s also a check ball in copper color and this may not be reused.

The TCI kit comes with spare check balls to ensure you can replace it if the original gets missing. You can then use the TCI instructions to reinsert the check balls while using some grease to hold them in place.

8. Insert a New Separator Plate and Gasket

A new separator plate looks similar but is still a bit different from the stock that came with the transmission. You can insert the new separator plate and gasket into the transmission, but it might be needful to modify the 3-4 accumulator using a self-tapping 1/4-inch x 20 Allen head plug. The accumulator piston and spring can also be replaced without using the black spacer.

9. Install the New TCI Valve Body

And after installing the gasket/plate assembly, it’s time to install the new TCI valve body. The rod for the valve body linkage can then be attached while ensuring that the valve is not forced and neither is the linkage bent.

10. Reinstall the Solenoid and Transmission Wiring

Also using the TCI instruction, reinstall the solenoid and transmission wiring. While at it, it may be useful to include a TCI lockup wiring kit to enable the torque converter clutch to enable flexible engagement of the automatic activation of the torque converter clutch in Fourth gear. This setup will also allow the clutch to disengage during acceleration or downshifts.

11. Reinstall the 1-2 Accumulator Assembly

The 1-2 accumulator assembly can be reinstalled after the piston has been mounted within the housing using a large orange TCI spring. The black spacer can also be installed if your ride is meant for street/strip applications. You can then fasten the bolts to 8 ft-lb.

12. Reinstall the Throttle Pressure Mechanism

It’s time to reinstall the throttle pressure mechanism and also the cable linkage while ensuring that the latter is well placed on the large lever. Other steps include running new wires, inputting oil pipe and tightening the bolts of the valve body to 8 ft-lb. In contrast, the detent roller spring bolt can be tightened to 10 ft-lb.

13. Replace the Filter

The TCI kit also comes with a filter seal ring and a new filter that you can use to replace the old one that was disposed of.

14. Revamp the Transmission’s Exterior

You can also revamp the exterior of the transmission by working on the servo. The parts of the stock servo can be replaced with the TCI parts before reassembling.
–

The Bottom Line

These are the easy steps to up the performance of your 700R4 rebuild without spending the extra cash to buy a new transmission. While these are DIY steps, you can employ the services of a professional if you’re unable to handle these procedures yourself. It’ll ensure that the transmission rebuild is just right and you don’t have a worse transmission than what you started off with.

In Transmission & Drivetrain

Ready to Modernize Your Chevy 4L60E Trans?

Ready to Modernize Your Chevy 4L60E Trans?-Gearstar

So, you’ve got a Chevy 4L60E trans and you think it can offer more power, speed, and even fuel economy? Then it’s time to make it happen. You may have taken the route of providing more horsepower to see that the car accelerates better.

However, if the transmission does not send this power to the wheels, you won’t really see a significant difference. But what if you could take the approach of making certain performance upgrades to this transmission, it’ll boost its power and give you the ride you desire.

And you’ll be surprised to know that a budget-friendly upgrade will enable the ride to handle up to 500 hp. Accordingly, we’ve outlined some tips that will help you to modernize your Chevy 4L60E trans.

 

About the Chevy 4L60E Trans

The 700R4 transmission gained several upgrades over the years which led to the launch of transmissions including the 4L60E/4L65E/4L70E. The 4L60E is an electronically controlled four-speed automatic overdrive transmission.

As an electronic version, this transmission may be a bit expensive to retrofit into an older car, but this version is easier to manipulate compared to dealing with TV cables and mechanical governors. On the other hand, the right performance parts can make the Chevy 4L60E trans a solid street overdrive automatic.

 

Modernizing the 4L60E Trans

Rebuilding the 4L60E can significantly improve its performance and this upgrade can be carried out using modern parts. Accordingly, the performance upgrades that can be implemented to modernize the 4L60E transmission include:

 

1. Replace the Pump

If the transmission’s pump is performing below expectations or is bad entirely, it calls for replacement. For starters, a pump that is underperforming can lead to low line pressure which can cause further problems.

This is because automatic transmissions apply clutches and servos with the help of hydraulic pressure. Hydraulic pressure is also essential for any performance-built automatic. But how do you begin?

Disassemble the unit and clean it before checking the clearances of the front pump. An elevated pressure regulator spring and boost valve may also help to improve the performance of the transmission.

 

2. Valve Body Modification

A simple 2-3 shift valve modification can bring about an improvement in durability, which is useful in performance driving. In this case, placing the shifter in “D3” uses the over-run clutch in the first three gears and this helps to improve durability since the input sprag is not abused. In contrast, the over-run clutch in OE configuration is applied when the shifter is in “D3” and after the transmission upshifts into Third gear.

 

3. Second and Fourth Gear Servos

Larger Second and Fourth gear servos can help to increase the piston apply area. The Second gear kit can offer as much as 18 percent more apply area compared to the OE Corvette servo.

As such, it could lead to a reduction in band slippage during upshifts and at the same time increase hold pressure. A customized Corvette-style servo, for instance, can potentially bring about a 35% increase in the servo apply area compared to a stock V-8 version. It can also offer better 1-2 and 2-3 shifts.

 

4. Enhance the Clutch Pack Clearance

Car rebuilders have noted time and again that a tight 3-4 clutch pack clearance (0.045-inch) could lead to excessive drag. This drag may occur in cases where the clutches are not applied in the first and second gears. What happens here is the drum spins but insufficient clearance can cause the clutches to glaze and fail prematurely.

Accordingly, a better approach is to set the 3-4 clutch clearance dry at 0.060-inch instead of 0.045-inch using return springs. These springs help the clutches to release fully. And for more increased stability, rear stator support, and wider sun gear bushings can also be used.

 

5. Wider Reverse-input Drum Band

A wider reverse-input drum band that is used with a new drum instead of an old one can also be beneficial. A wider band over a used drum allows the band to span the drum’s worn portion. A new reverse-input drum is useful to ensure that the band does not fail quickly.

 

6. Use a Reinforcement Kit

An input housing reinforcement kit is useful in preventing the transmission’s housing from cracking right where the input shaft is fixed. Clutches may be susceptible to certain problems and notable among this is an excessive backing plate flex once the clutches are applied.

On the other hand, an Ultimate 3-4 Smart-Tech housing can be used with a stronger input shaft to increase the housing depth with a 0.165-inch greater capacity. This capacity will allow more clutches to be supported but not at the expense of steel thickness.

Moreover, the 3-4 housing takes advantage of a 15-bolt retaining ring cap which shows renewed strength and, therefore, helps to eliminate deflection.

 

7. SmartShell Reaction Shell

One more way to bring about significant improvement in durability is to take advantage of a SmartShell reaction shell. A custom SmartShell reaction shell can offer improved durability compared to the original piece which is prone to failure. For starters, the customized variant may feature a thrust bearing as a replacement to the OE bushing along. This setup can also be paired with a custom roller clutch race.

 

The Bottom Line

Performance parts can help to build a Chevy 4L60E trans that will meet your heart’s desire for power and speed. It’s not all about boosting the horsepower and at the end of the day, not still get the required performance. Rather, it involves taking the extra time to revamp this trans to handle modern-day driving needs.

Moreover, the upgrades to be made using these parts are inexpensive, and as such, you can get them fixed in no time. And if you do not have great expertise to handle this rebuild yourself, let an auto shop handle it on your behalf. That being the case, you’ll still have a ride that is better than what you started off with.

 

In Maintenance, Transmission & Drivetrain

6 Ways to Prolong the Life of Your Performance Transmission

6 Ways To Prolong The Life Of Your Performance Transmission-Gearstar

There are several ways to prolong the life of your performance transmission, and if you employ them, it’ll save you from making huge expenses in the long run. A transmission is one of the most expensive components in a car and as such, a replacement could take a huge chunk out of your wallet.

And that may be the least to worry about since serious issues that arise in your transmission may be difficult to repair. Nonetheless, you can cut costs and at the same time, avoid potential transmission problems just by applying certain tips. These tips will help to extend the life of your performance transmission.

 

A Great Performance Transmission

Transmission in a manual or automatic car helps to transfer power from the engine to the wheels. What this power transfer does is to enable the car to change its gears and also move in the desired direction.

Now if your transmission is in bad shape, it either has to be overhauled or replaced entirely. The process is expensive and may become a bitter pill to swallow. But the good news is, it can be avoided by carrying out certain checks.

 

How to Extend the Life of Your Performance Transmission

You can extend the life of your performance transmission by doing the following:

 

1. Check the Transmission Fluid Regularly

Transmission fluid helps in cooling and lubrication, and it transmits force and pressure, while also preventing build-up. Therefore, one surefire way to prolong your transmission’s life is to check its fluid regularly.

The transmission fluid may run low or contain impurities as it gets old. When either of these happens, it could lead to common transmission problems such as overheating. Nonetheless, overheating can be avoided if you know just the right time to refill or change the fluid entirely.

Now you may be wondering, how often should you check the transmission fluid? You can inspect the fluid once every month to ascertain its level and condition.

Pick up your dipstick and check the level of the transmission fluid, and if it looks opaque instead of clear red, then the fluid is bad and needs to be changed. Similarly, if you give the fluid a good whiff and perceive a foul smell, then it could be a sign of a problem.

 

2. Use Synthetic Fluid

Synthetic transmission fluid is more preferable than ordinary fluid for a number of reasons. For starters, a synthetic fluid is better at resisting cold, heat, oxidation, and shearing. Heat, on the other hand, can break down the organic compounds in a regular fluid thereby making it less effective.

Therefore, if you want your transmission to last longer, synthetic fluid would be your go to option. Heat-resistant, synthetic fluid will help an aging transmission to still offer good performance over time.

A good number of manufacturers are already replacing regular fluids with synthetic fluids in a bid to ensure that the vehicle is not impacted by certain elements. In line with that, it is worth noting that poor quality fluid can harm your transmission; hence, the high-quality fluid must be used at all times.

 

3. Service Your Transmission Every 30,000 Miles

Your transmission can last for 300,000 miles or more if it is serviced regularly. The reason can be tied to the fact that the transmission can fail within 100,000 miles. What this means is that if you tend to drive around 10-15,000 miles a year, the unit could be down in seven years. Here’s what we’re getting at:

Another way to extend the life of your performance transmission is to get the unit serviced every two years or 30,000 miles. During the servicing process, one of the most effective maintenance procedures will be carried out on your vehicle and that is changing the transmission fluid.

Accordingly, the old fluid will be drained from the transmission, and the pan will be cleaned.  The filter will then be replaced before new fluid is poured into it. At the end of the day, you would’ve been able to enhance the performance of your car just by changing the fluid and allowing its filter to work better at trapping dirt.

Interestingly, a service of this nature would cost you around $60-$100 or less depending on where your car is being serviced. If you want to reduce the cost of servicing your transmission even further, learn to carry out the process yourself.

 

4. Use an External Filter

You may have taken the needful step to clean your transmission’s filter. But an external filter to the cooler lines can also help to keep dirt away from the fluid. This is because the original filter may be unable to handle all the particles it may encounter, hence an external filter will help it to do a better job.

In the end, more contaminants will be trapped and the transmission fluid will be as clean as possible. Much more, the fluid will be clean for a longer time compared to when a single filter is used.

 

5. Maintain the Cooling System

Your car’s radiator also serves to cool the engine since heat can cause a lot of damage to the transmission. While you may have a radiator in place, its level of performance may reduce with time, which is why it is advisable that you maintain it every two years.

These maintenance checks will involve inspecting the coolant levels, changing the antifreeze, and inspect the hoses and belts. Other checks you can carry out include carrying out a radiator cap pressure test, and a thermostat check.

A transmission cooler might also prove very useful if you tend to travel in environments where the temperature of the transmission might be raised to high levels. The same applies if you drive with heavy loads frequently, or in heavy traffic.

 

6. Practice Good Driving

It is important to drive your car more easy. Especially on a cold start since transmission fluid is thicker when it’s cold. If the fluid does not move well from the bottom to the top, it could lead to friction thereby causing damage.

What’s more, the transmission takes time to warm up and if it doesn’t, you may be putting too much strain on it. The point is, don’t drive even before the transmission has warmed up.

If it is in cold weather, let the car idle. When the engine’s RPM has lowered, the vehicle can be put into gear. Asides from being easy on the unit, you can use the emergency brake when you’re parking on an incline, and avoid resting your hand on the gear lever as you drive.

 

The Bottom Line

These are the easy steps on how to prolong the life of your performance transmission. It revolves around checking your transmission fluid regularly, setting scheduled fluid changes, band adjustments and using more than one filter.

There’s also the need to ensure that your radiator is functional. This will help to minimize the heat produced by the engine while in operation. Try each of these and you’ll be able to extend the life of your transmission for a couple of years if not more.

Most importantly, it’ll help you to save thousands of dollars that would have been wasted on premature transmission failure.

In Transmission & Drivetrain

4R70W Transmission-Swapped Fourth-Gen Mustang?

4R70W Transmission-Swapped Fourth-Gen Mustang? - Gearstar

The fourth generation Ford Mustang can be made faster and more reliable by carrying out some performance upgrades instead of adding more power. It may involve installing a performance automatic 4R70W transmission in a bid to change the stock unit that came with the vehicle.

While a stock transmission comes directly out of the manufacturer’s warehouse, it may be unable to handle your need for speed. The latter can be tied to the Two Valve it features, which may leave the car struggling to get enough RPM (Revolutions per minute). Remember, if it gets enough RPM without struggling to, it takes it one step closer to being a faster ride.

Accordingly, the modifications or boost you can give the Mustang will provide a nose that is significantly higher than what a stock Two Valve can. The aim is to meet or exceed the original equipment manufacturer’s (OEM) measured standards.

But first…

What Is a 4R70W Transmission?

The 4R70W was launched as an improved version of the AOD-E transmission. And compared to the AOD-E, the 1st and 2nd gear ratios of the 4R70-W are numerically higher. This resulted in:

    • Better gearset strength
    • Lower fuel consumption
    • Better take-off acceleration
    • Better mechanical advantage

This Ford transmission is also an upgrade to the AOD, a 4-speed automatic overdrive transmission, aimed at tackling fuel efficiency issues. Upon its launch, the transmission featured a “wide ratio” gear set, however, a mechanical diode replaced its intermediate one-way clutch in 1998.

Often times, upgrades to the Mustangs with the 4R70W transmission are made possible using 4.10 rear end gears, shift kits, and a performance torque converter.

4R70W Transmission Specs

The 4R70W transmission specs are:

    • Transmission: Ford 4R70W
    • Predecessor: Ford AODE
    • Type: 4-speed overdrive automatic transmission
    • Wide gear ratio
    • Rear-wheel drive
    • Case Material: Aluminum
    • Max Input Torque: ~ 516 lb-ft (700 n-m)
    • ATF Type/Spec: MERCON V ATF (Motorcraft XT-5-QMC)
    • Transmission Filter: Motorcraft FT105

Gear ratios:

    • First: 2.84 :1
    • Second: 1.55 :1
    • Third: 1.00 :1
    • Overdrive: 0.70 :1
    • Reverse: 2.32 :1

4R70W Transmission-Infused Vehicles

Cars that used the 4R70W transmission include:

    • Ford F-150 Series pick-up trucks, E-150 Series vans, Expeditions, Explorers, Crown Victorias, Thunderbirds, and Mustangs
    • Lincoln Town Cars and Mark VIIIs
    • Mercury Grand Marquis, Cougars, Mountaineers and Marauders

Specifically, the years this transmission was used are:

    • 1993–1998 Lincoln Mark VIII
    • 1993–2003 Ford F-Series
    • 1994–1997 Ford Thunderbird
    • 1995–2004 Ford Crown Victoria
    • 1996–2001 Ford Explorer
    • 1993–2004 Lincoln Town Car
    • 1994–1997 Mercury Cougar
    • 1995–2004 Mercury Grand Marquis
    • 2003 Mercury Marauder
    • 1997–2004 Ford Expedition
    • 1997–2001 Mercury Mountaineer
    • 1996–2004 Ford Mustang
    • 2004–2005 Rover 75 V8

On the other hand, the 4R70W was not the only transmission for Mustangs.

This is because Ford had launched a range of transmissions since 1979 for Mustangs, and as such, you can find a wide variety of these transmissions. Other models include:

    • C4 Transmission
    • Automatic Overdrive or AOD Transmission
    • AOD-E Transmission
    • 4R75W Transmission
    • 5R55S Transmission

How to Boost Performance in a 4th Generation Mustang

A performance automatic 4R70W transmission can be used to boost the performance of a fourth generation Mustang. This is because a well-built automatic transmission and a torque converter with the right specs can give you car a good boost.

In that regard, this boost can be made possible by replacing the stock automatic-equipped Two Valves in the ride. Why is that?

The stock transmission is not known to offer an out-this-world performance due to the fact that a stock converter does not really perform to its best when it lacks low-rpm torque. In the same vein, the slushy shifts it makes shows that it is spending more time between gears rather than driving forward.

Nonetheless, some stock 4R70W-equipped light bolt-on New Edge GTs move speedily and even cover the quarter-mile in the low 15-second to high 14-second range. Much more, this performance is carried out seamlessly.

Accordingly, what you need to begin, is the right aftermarket parts to bring out their best performance. It all begins with a transmission upgrade.

Advantages of a 4R70W Transmission Upgrade

An automatic transmission upgrade can help with your ride’s performance, hence, it is a good place to start instead of adding more power. Here are some benefits that can be obtained from this transmission upgrade:

    • An upgrade will enable the car to shift gears faster and hold more power.
    • The performance converter will be able to move the car into the powerband sooner.
    • The upgraded components will be able to withstand the converter being locked under WOT.

Consequently, adding more power is not the most ideal solution since a good number of stock automatics tend to fail in short order once more power has been added. It could mean more problems in the long run, but it can be avoided by starting from the basics through a transmission upgrade.

4R70W Transmission Problems

Asides from upgrading your transmission to get more speed, it can help to improve its reliability. This is because there are certain 4R70W transmission problems that are prevalent with the stock transmission. For starters, the stock 4R70W transmission was susceptible to the following issues:

    • Harsh 2-3 shift
    • Delay in lock-up
    • Loss of second gear and third gear
    • Loss of fourth gear and forward gears
    • An intermediate clutch failure
    • Delay in reverse or shudder in reverse
    • Leaking of the front seal or pump noise

The Bottom Line

The 4R70W is a good transmission, however, it can be made to perform even better in a fourth generation Ford Mustang. In this case, the usual route of adding more power is not employed, instead, a transmission upgrade is carried out to ensure that whether you’re out for drag racing or performance driving, you can get good speed.

What’s more, an upgrade from the stock transmission will eliminate certain issues that were prevalent in it. These issues include loss in gears, delays in lockup, clutch failure, and many others. Once each of these is eliminated, it can go a long way to improve the reliability of your transmission and also help it to offer more power boost.

In Transmission & Drivetrain

Overview of the GM TH400 Transmission

The GM TH400 Transmission: An Overview - Gearstar

 The TH400 or Turbo 400 is a good transmission that was used in several cars years ago. This popular transmission was found in GM’s cars, as well as, Rolls-Royces, Jeeps, Jaguars, Ferraris, etc. The TH400’s high-level of adoption could be tied to its remarkable features, and it proved that people can once again rely on GM transmissions.

But what were these features sported by this durable and legendary transmission, and generally, what set it apart from other transmissions from this manufacturer? An overview of the TH400 transmission will give you a better idea. Read on to find out!

 

The GM TH400 Transmission

The GM TH400 transmission is a three-speed automatic transmission that was longitudinally positioned behind the engine. This placement is aimed at providing the best power ratio and durability for rear-wheel drive. The TH400 has been rated at 450 ft. lbs. of input torque, nonetheless, aftermarket designs that have been modified may go beyond that rating.

 

History of the TH400 Transmission

The TH400 was launched by General Motors in 1964, as a replacement to the ST300 2-speed automatic transmission. It was used in a wide range of vehicles, hence, it was not just exclusive to GM cars.

Upon its launch, the TH400 was evident in Buicks and Cadillacs, and a year later, it was used in Chevrolet and Oldsmobile cars. Buick, Olds, and Cadillacs that were later launched between 1965-1967 also featured the transmission but with an innovative variable-pitch stator. This stator helped to vary the torque converter’s characteristics, and you can tell a car has this stator by the two-prong plug on the case.

In the 1970s, the TH400 was used in heavier-duty GM trucks and it was available in 2wd and 4wd configurations. The naming of the TH400 was changed to 3L80 (3-speeds, Longitudinally positioned, 8000 lbs. GVW or Gross Vehicle Weight) in 1990 to make it easier for buyers to identify the transmission.

The change in naming does not come as surprise since some GM transmissions were also renamed (for example the 700R4 to 4L60). Around the same time when the TH400’s name was changed, an overdrive version called the 4L80-E was launched.

This is an electronically controlled transmission that is still being produced and used in a range of heavy-duty GM and military cars/trucks. Generally, here’s a list of cars that used the TH400 transmission:

    • 1965-1967, 327 V8 (Rambler/AMC)
    • 1968-1971, 350 V8 (Buick)
    • 1969-1972, 225 V6 (Buick)
    • 1972-1975, 232 I6 (AMC)
    • 1975-1979, 258 I6 (AMC)
    • 1972-1979, 304 V8 (AMC)
    • 1972-1979, 360 V8 (AMC)
    • 1974-1975, 401 V8 (AMC)
    • GM
    • Jaguar
    • Ferrari
    • Rolls-Royce

 

Features of the TH400 Transmission

The features of the TH400 Transmission enabled it to provide improved performance over previous transmissions. It was also durable, and these characteristics can be tied to the following:

    • Aluminum and iron construction.
    • Weighs 135 pounds without fluid.
    • Bell housing integrated into the transmission.
    • First gear: 2.48:1, Reverse gear: 2.08:1, and third gear is an even 1 to 1.
    • Came with three tail shaft lengths.

 

Turbo 400 Transmission Identification

The Turbo 400 transmission can be identified in the following ways:

1. External Build

The TH400 transmission comes with a case made of cast aluminum alloy to give it strength and durability. The case is very smooth and its length sits at length of 24-3/8″ long. This TH400 is the largest of the common GM automatic transmissions, however, the transmission still maintains a compact design.

There is a hex bolt pattern on the rear mounting face of the transmission and the ribs run forward longitudinally. In line with that, the fluid pan has an irregular shape.

2. Variants of the TH400

There are two variants of the TH400, and these are the TH375 and TH475. The TH375 was used in smaller displacement cars between 1972-1976. In contrast, the TH475 was used in larger trucks from 1971 since it is an extra-heavy-duty version. One can easily different either these variants apart by looking out for the “375-THM” designation cast on the bottom of the tail housing.

TH350 vs. TH400

A simple way to differentiate them is to check the kick-down mechanism. The TH400 transmission takes advantage of an electrical slide switch controlled by the throttle linkage. On the other hand, the TH350 uses a mechanical cable kick-down that is connected to the throttle linkage. Despite the difference, the TH400 is considered the heavy-duty version of the Turbo-Hydramatic 350.

 

Transfer Case of the TH400 Transmission

The TH400 can easily be adapted for use in most Jeeps longer than CJ5s, and as such, it is an excellent conversion transmission. Whether it’s the 2wd and 4wd versions of the Turbo 400, either of these can be used. Nonetheless, the 1976-1979 AMC case is similar to that of the TH400’s, from the collar of the case and back, however,  it is tilted about four degrees.

 

Engine Compatibility and Adaptability

The engine compatibility and adaptability of the TH400 transmission include:

1. AMC/Mopar Jeep

The earliest Turbo 400s in Jeeps featured a factory adapter plate, whereas older AMC versions came with a dedicated AMC style case. It is entirely possible to make the Chevy 400  compatible in the AMC I6 & V8 engines. As an upgrade of this nature can result in a more enhanced Jeep powertrain over 727, 999.

2. Chevrolet

The front face of the TH400 is compatible with the Chevy 90 degree “Small Block” or the “Big Block” patterned engines.

3. Buick / Olsmobile / Pontiac / Cadillac

The TH400 is compatible in Buick engines especially when you use a Buick V8 or V6 version of the transmission.

 

Common TH400 Problems

The TH400 may have offered improved performance over its predecessor, the ST300, but it still came with its own problems. Notable among this is an early shift and less efficiency when the engine revs high. The latter occurs when the kick-down switch, responsible for shifting between gears and maintaining maximum RPMs, stops working. The switch would’ve helped in, efficient power usage.

On the other hand, the cause of this problem can be tied to the wrong placement of the vacuum hard-line, moving from the intake manifold with a pliable rubber line. The heat generated by the engine and transmission leads to the deformity of the rubber, thereby failing to hold the pressure properly. Another problem of the TH400 is the possibility for its transmission fluid to leak gradually into the hose if the seal is not fixed properly.

 

The Bottom Line

An overview of the TH400 transmission shows it is a durable transmission that can give a good performance. The TH400 was used in a wide range of cars from GM as well as other manufacturers. Interestingly, the transmission can be adapted for use in several engines today. In the end, whether it’s a new or aftermarket TH400 you settle for, you are bound to get the full benefits offered by this transmission.

 

Close Menu