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October 2020

Top Signs It’s Time for a Transmission Rebuild

Top Signs It's Time for a Transmission Rebuild - Gearstar Performance Transmissions

 Keeping a close eye on the top signs it’s time for a transmission rebuild will ensure the proper functioning of your transmission for a long time. It will also save you money in the long run due to the importance of this piece of machinery in your car. In this case, the transmission is responsible for moving power from the engine to the wheels through a series of gears.

The transmission is also a highly intricate unit with several moving parts, which requires scheduled maintenance to keep these parts running at their best. Accordingly, whether your car has a manual, automatic, or semi-automatic transmission, here are top signs it’s time for a transmission rebuild.

Warning Signs of Transmission Trouble

So, when does a transmission need to be rebuilt? Let us show you some of the signs to be on the watch for. And if you spot any of these signs of transmission failure, contact your local repair shop to get the unit fixed immediately.

Grinding Gears

Got trouble shifting and even hearing a sound like two metals grinding on each other? Then it is a top sign of transmission issue. This issue may stem from low or no transmission fluid in the gears. Another possible cause of grinding gears is if the gear teeth have worn out. That being said, the latter issue can be resolved by rebuilding the transmission to revive it again.

Leaking Transmission Fluid

If your transmission fluid is leaking, then it is a major cause for concern. But how can you tell when this fluid is leaking? You need to keep a close eye for a red fluid discharging from the transmission. Continuous leaking of the fluid will lead to low transmission fluid levels, which could hinder the operation of your automatic transmission and impact negatively on your car.

Therefore, get this issue checked as soon as possible and keep in mind that a full transmission rebuild may be needed to resolve it. Nonetheless, you can easily replace the seal that is leaking before refilling with fluid if the leak is minimal. The reverse is the case if the leak has occurred for several miles and thus, a full rebuild is needed.

Slower Shifting

If your automatic transmission lags while trying to shift and does not respond immediately, you may need to take a closer look at it. This delayed shifting may be caused by low transmission fluid. Therefore, add more fluid to the reservoir and take the extra step to inform a mechanic of the issue. On the other hand, if your transmission will not even shift into gear or reverse, a rebuild may be needed. The problem stems from worn-out gear teeth that prevent the transmission from engaging.

Burning Transmission Odor

Detecting a burning odor that can be likened to that of burning plastic is a sign of a faulty transmission. Here, transmission fluid lubricates the moving parts within the mechanism, and this smell could indicate that the transmission fluid is overheating. A problem of this nature needs to be fixed immediately to prevent the unit from failing completely. The odd smell may also indicate that your car’s clutch needs to be repaired or adjusted.

Strange Sounds

It can save you money in the long run if you do not ignore any weird sounds that your transmission is producing. These weird sounds may be produced when the car is in neutral or while shifting or driving. Some sounds you should keep an open ear to include whining or grinding and either of these indicate that there may be problems with your transmission. Accordingly, get a repair specialist to examine your vehicle and make a proper diagnosis of the issue.

Popping Out of Gear

Your car may tend to pop out of gear every now and then which is a sign of a mechanical problem. This issue can impact on the ride and even pose a risk to the driver. This is because each time the car pops out of gear, it could make it difficult to properly control the vehicle. It also means you could smash into other cars and put its passengers at risk. That being said, call a technician to come to look at your car to get the issue fixed.

Is a Transmission Rebuild Worth It?

Many have wondered. “Is it worth getting a transmission rebuild?” The answer is yes especially if it has been recommended by your car technician or the repair shop you are using. And most importantly, if you experience any of the signs listed above, then it will be worth giving your transmission a rebuild to get it running smoothly again.

What to expect after a transmission rebuild makes the whole process worth it. It gets even better when you do not skip the scheduled transmission maintenance for your ride and have a professional in the field handle its rebuild. The technician will get the transmission repaired before it gets worse.

The Bottom Line

The top signs it is time for a transmission rebuild should always be at your fingertips to ensure your transmission is always in good condition. These signs may vary depending on the cause, hence, do not ignore them each time you spot one or the other.

The goal is to enable the transmission to carry out its basic function with ease and reduce the potential for your vehicle to break down unexpectedly. Therefore, it is up to you to ensure your sleek ride is always in good shape to hit the road.

How to Choose the Right Performance Transmission Fluid

How to Choose the Right Performance Transmission Fluid - Gearstar Performance Transmissions

There are several automatic transmission fluids on the market today, which could make it a bit challenging to ascertain the best fluid for your car. However, that should no longer be the case given that we’ve outlined easy ways on how to choose the right performance transmission fluid for your car. Prior to this time, the decision of choosing between fluids was easy since cars basically relied on two-fluid types.

These fluids were Type F and GM’s DEXRON. Today, the need for improved fuel mileage has led OE manufacturers to create their own fluid, which is why you will find different automatic transmissions fluids. There are Chrysler‘s +3 and +4 fluids, seven fluids from Ford, and DEXRON versions III and VI fluids. So, how can you choose the right performance transmission fluid for your car? Read on to find out!

Selecting the Right Automatic Transmission

Some reasons why you need the right automatic transmission includes:

1. Requirements

Although there is a vast array of car lubricants from different manufacturers, each maker has designed its specific fluid to meet a narrow set of requirements. The increase in the number of gears and various automatic transmission types has also increased the types of fluids on the market.

2. Backwards Compatibility

There are often claims that the latest ATFs are backwards compatible, but the latter is not always the case. An instance is the GM 4L60E automatic transmission in the 2000 Camaro or Corvette. Here, the DEXRON-VI is often recommended as the best fluid for this transmission since it has a lower viscosity fluid and a more stable viscosity at a higher temperature.

On paper, it would mean that the DEXRON-VI is also backward compatible with older transmissions like the TH350 and TH400 transmissions. But this is not the case given that DEXRON-VI is best for newer vehicles.

First off, DEXRON-VI was released in 2005, which means older transmissions were filled with DEXRON-III from the factory. While DEXRON-VI will work in these transmissions, recent experiments of DEXRON-VI in cars originally designed to use DEXRON-III showed a slight increase in the converter stall speed.

Choosing the Right Performance Transmission Fluid

To choose the right performance transmission fluid for your car, consider the following:

Type F Transmission Fluid

For transmissions designed after 2000, it is ideal to use the most modern ATF. This is because automatics made in the twenty-first century are designed to use fluids with added friction modifiers additives to soften clutch engagement. And for transmissions designed before 2000, it is better to settle for a more traditional fluid.

A good fluid that is recommended for most older transmissions is Ford Type F fluid. There is the original Ford Type F fluid, and it was formulated with a reduced friction modifier package. This design was intended to create quick clutch engagement and reduce clutch slippage. It is also possible to use the DEXRON-VI in these vehicles even though they are not the best choice, which means you can opt for the DEXRON-III fluid.

Transmission Fluid Additives

There are companies that create different versions of the Type F fluid to aid drag racing. These versions often include a 20 weight and 30 weight version, and both are pure synthetic fluids. A heavy car that has more torque will rely on the 30W while other cars can use the lighter fluid. The lighter fluid can also be used to adjust stall speed significantly higher.

While it may be useful to use these synthetic fluids, it is worth noting that you should not mix fluids that have different additive packages. An instance is the Chrysler +4 fluid that relies on a different additive package compared to DEXRON, and Mercon.

Multi-Vehicle ATF

Several companies have launched multi-compatible fluids to ensure you choose the right one for your car. There are fluids that are a combination of DEXRON and Mercon fluids. However, the factory specs of each fluid vary even though it is close enough for a single ATF to achieve both.

On the other hand, do not settle for fluids that claim to be suited for all vehicles. The reason lies in the fact that a more universal fluid is not ideal for a performance transmission. In line with that, do not use ATFs intended for continuously variable transmissions (CVT) on older automatics.

The same applies to fluids that are labelled as low viscosity (LV) or ultra-low viscosity (ULV). This is because these fluids consist of unique friction modifiers that are meant to meet certain mileage goals. These goals are counter-productive to a performance application.

Synthetic Transmission Fluid

Synthetic transmission fluid refers to the quality of the base oil, which is important for temperature stability. Accordingly, it would be useful to settle for a pure synthetic base stock since it is the best ATF to use for your performance transmission. Synthetic ATF offers superior thermal stability, which is beneficial for performance automatics with high-stall converters that tend to generate a high amount of heat.

The heat can impact on the fluid’s addictive packages negatively and thereby reduce their performance. In contrast, a more stable synthetic ATF will not lose its qualities over an extended time and it can withstand high temperature to still protect the transmission from damage.

The Bottom Line

These are the simple steps on how to choose the right performance transmission fluid for your car. Following this guide will ensure you choose a fluid that can is right for your performance transmission. Your automatic transmission will perform to the best of its ability and stand the test of time with the right lubricant in it.

On the other hand, older transmissions launched before 2000 can also benefit from the use of fluids originally made for them. The bottom line is the right fluid will offer the best performance during drag racing and save you frequent trips to the repair shop.

GM Transmission Recommendations for High Performance

Turbo 350 Transmission - Gearstar

Here is our guide to the GM transmission recommendations for high performance to ensure you get the best automatic transmission for drag racing. You will be getting an engine that is durable, lightweight, and efficient. First off, GM overdrive automatics are quite popular on the street, whereas powerglide and TH400 are notable on the staging lanes of dragstrips.

Race cars such as street/strip machines, Fords, Mopars, Chevys, Top Alcohol dragsters, or 3,000hp Outlaw 10.5 beasts rely on drag racing transmissions from GM or bust. Accordingly, we have outlined some recommendations to look forward to and factors to consider such as reaction time, OE durability, and powerglide perks.

GM Transmission Recommendations for High Performance

Here is a more detailed outline of our top GM transmission recommendations for high performance. They include:

Powerglide vs TH400

The powerglide and TH400 are often used as the standard for durability in competitive drag racing. There are applications where the powerglide is better used, and certain cases where the TH400 is more suited. But what application are each of these suited?

The powerglide is a better option when dealing with cars that do not weigh more than 3,200 pounds. These vehicles also launch violently and may be traction limited. And when dealing with race cars, the TH400 is ideal for cars with large tires and taller rear end gearing.

TH350 Alternative

There is the TH350, which is a good compromise when compared to the TH400 and powerglide. The TH350 has something similar to the TH400, which is its three forward gears with less rotating mass. On the other hand, the TH350 may need expensive components to be on par with the powerglide or TH400 to handle all the racing you may need without intermediate sprag or snapping the input shaft.

The stock versions of the powerglide and TH400’s planetaries, drums, and shafts are more rugged than the TH350. That is not to say that the TH350 cannot be upgraded to be on the same level with entry-level powerglide and TH400s that have been enhanced with premium frictions and steels. In this case, the upgrade can be made possible with a sprag-type intermediate overrun clutch, a late 700R4 low roller clutch center support, a 300M input shaft, premium racing frictions and steels, and a shift kit.


Drag racers give serious consideration to performance differences between GM transmissions. Other factors that need to be considered include size, weight, and efficiency. Accordingly, powerglide and a TH400 have a similarity in width whereas their length differs.

Their length may vary between 18 inches on a dragster-style powerglide to 28 inches in a door car. That aside, the TH400 using a standard 4-inch extension housing has a measurement of 29.5 inches. There are times where the transmission measures 34.5 or 38.5 inches.


Servicing your drag transmission can help to prolong its life. This servicing can be carried out every week. It may be useful to drop and inspect the pan after every race weekend on a Monday to ensure unusual debris is taken out of the unit and the unit serviced before the next race day.

On the same note, the powerglide or a TH350 has a filter which is the screen and should be removed and cleaned. You will find a felt or screen element type of filter TH400s and if this is a felt-type filter, it needs to be replaced weekly. There is also a need to replace the pan gasket and torqued to 12-15 lb-ft.


Heat can wear down your transmission especially when the fluid has broken down and viscosity is lost. It is often recommended that you run a temperature gauge to be able to ascertain if the transmission is becoming hot.

If the transmission is around 160 and 180 degrees, you can change the fluid every 40-50 passes. However, if the temperature is ranging around the 200-230 degree mark, it is useful to take proper measures to reduce the operating temperature and fluid changes.

And in cases where the temperature is low, it is useful to use thinner fluids whereas thicker fluids can be used in applications where the temperature surges. Engines with big horsepower engines equipped with automatics often rely on thicker fluids.

Reaction Time

In a bid to win races, you need to make certain modifications to the trans brake. These modifications will offer quick response time and consistent performance. You may be out to get fast-releasing brakes coupled with slower brakes. The slower brakes could help when you need to slow down.

Aside this, you can do certain things internally to the transmission to bring about quicker response time. While using a powerglide, your trans brake can be engaged by holding low gear with the band and Reverse with the band. The reverse clutch area can be used to remove fluid out of the cavity faster to ensure the reverse clutches disengage sooner.

OE Durability

Stock powerglide parts are robust and they are often installed behind six-cylinder engines. There are also powerglide that were installed behind V-8s and these ones featured heavier-duty 1.76:1 ratio planetary set that can support 700-750 hp. There is the 1.82:1 ratio planetary and it is rated at 500-550 hp.

What is more, the factory powerglide, and these ones were the real internal difference. In this case, other internal components are often in the same when it comes to durability and strength. That being the case, the strongest OE-style powerglide is reliable for 750 hp in a 3,000-pound car.

The Bottom Line

The GM transmission recommendations for high performance outlined above will ensure that your ride is better prepared to handle drag racing. It will be rugged, fast, and generally offer impressive performance. If that is what you are out to get, try these recommendations today.