Skip to main content
Monthly Archives

January 2018

Upgrading a 4L70E Transmission

Upgrading a 4L70E Transmission - Gearstar Performance

The 4L70E is one of several GM-produced electronic automatic transmissions developed as a successor to the Turbo-Hydramatic line of transmissions, some of which continue to be excellent transmissions for plenty of performance builds looking for a good stock transmission with a TV cable over electronics.

Alongside the 4L60E on one spectrum, and the 4L80E on the other, the 4L70E sits between two ends of spectrum of transmission needs.

Depending on what you want, it may be an excellent transmission and just the thing you’re looking for. It’s all a question of specialization. Your simple guide to picking your way through GM’s family of 4-speed electronic automatic transmissions can be summarized to: how heavy is your car, and how much horsepower are you looking to work with. Heavier builds steer towards the larger, more imposing, power-hungry and powerful 4L80E, and the smaller your car is, the more you should be skewing towards the 4L60E.

But life isn’t always simple, and in this case, there’s more to it than just that. Here’s a quick little rundown on the 4L70E, its relative history in the world of GM transmissions, and its potential – potential that transmission experts can take, unlock, and transform into pure performance.

History of the 4L70E

GM’s transmissions play a big part in the history of American automobile manufacturing, and alongside Ford (a “friendly” competition that survives to this day), the automatic transmissions of the late 70s and early 80s pioneered the inclusion of accessible overdrive – a new gear made more accessible to transmissions after that point, designed to allow a car to maintain speed while cutting down on RPM and fuel usage, for a much better fuel economy.

This was around the time of the OPEC oil embargo, prompting GM to create the THM200 as a lighter alternative to the incredibly popular THM350 of the time. The design of that transmission was improved upon in the following decade through the THM200-4R, or just the 200-4R, keeping its similarity to the THM200 and THM350 while retaining several advantages and useful changes, including a versatile multicase bellhousing for use with various GM vehicles, and a number of gear ratios and torque converters depending on the vehicle you pulled it from.

Following the success of the 200-4R, the next-in-line kept the new designation, and the 700R4 transmission was born in 1982. This is the first of our new automatic transmissions, as the 700R4 eventually was renamed into the 4L60, in keeping with a new GM naming scheme, in 1990. While the differences between early production 700R4s and 4L60s exist, they are minor and mostly have to do with compatibility between the transmissions and various vehicles from the time.

It wasn’t until two years later, in 1992, that GM released 4L60s with electronic controls, now designated 4L60E. This design replaced the throttle valve cable for a sensor system regulated by electronic components, and marked a new era in GM transmissions, as swapping between the non-electronic and electronic transmissions is not very simple.

Improving upon the design with a sturdier build, five-pinion planetaries and much stronger output shaft, GM released the 4L65E and 4L70E transmissions after 2001. Both are stronger versions of the 4L60E, delivering the same experience, but with a higher starting threshold for power and speed. The only difference is the speed sensor located in the pump of the 4L70E, and the convenience you personally have in picking between one and the other depending on your available resources, market prices, and any existing deals.

4L70E Transmission Stats

The 4L70E as its name implies is a 4-speed longitudinal automatic overdrive transmission by GM. The E in its designation indicates that it uses electronic controls over a throttle valve cable, and it sets itself apart from the previous 4L60E by providing a sturdier build, including both five-pinion planetaries over the 4L60E’s four-pinion planetaries, and an improved output shaft. Its outer case material is aluminum, and it clocks in at about 133 lbs. dry, without any transmission fluid.

Although it is improved, it shares the same stock case design with the 4L60E, and its close cousin the 4L65E. All 4L__Es utilize a torque converter lock, and the 4L70E is no exception.

The gear ratios for the 4L70E are:

  • 1st gear: 3.06
  • 2nd gear: 1.62
  • 3rd gear: 1.00
  • 4th gear: 0.70

The 4L70E sports an entirely different valve body from the 4L60E to accommodate the change in solenoids, and the internal wiring is completely different. Care needs to be taken when deciding how to install a 4L70E in cars that originally used an older GM transmission – while it often bolts just in, the car may not be compatible with the electronic components in the 4L70E if it’s a model before 1996. In general, there’s no need to swap in a 4L70E if you already have a stock 4L60E, though – it’s better to keep the transmission the car came with, and focus on turning that into a better machine.

4L70E vs. 4L60E vs. 4L80E

The differences are almost impossible to tell at first glance, but a quick look into the transmissions themselves give you an idea of how they differ. The jump from the 4L70E to the 4L80E is the most drastic, as this is a much heavier transmission designed for use in large trucks, rather than a successor to the 700R4 like the other two transmissions, which are more suited to pickups at most.

The 4L80E weighs 178 lbs. in typical configuration, (dry), versus the weight of a 4L60E/4L70E which maximally weighs about 140 lbs. Your best bet towards visually distinguishing between the 4L60E and the 4L70E is checking the service parts identification sticker if it’s the stock transmission in a GM vehicle. Look for M70, which denotes the 4L70E. Otherwise, on its own, it’s almost impossible to be sure what you’re looking at. They all use the same oil pans and the designations are interchangeable depending on the year and build of the transmission.

Between the 4L60E and the 4L70E, the biggest difference is time. The 4L70E is a straight upgrade to the 4L60E, appearing on the market several years after the 4L60E has had time to shine. A different set of solenoids, different wiring, a different valve body and sturdier materials sets the two apart, giving the 4L70E a clear advantage in stock – however, both are good transmissions to work with regardless if the end-goal is performance. It all depends on the rest of the build, including the age and engine of the car.

Overview of GM’s Stronger 4L65E Transmission

Overview of GM's Stronger 4L65E Transmission - Gearstar Performance

The 4L65E transmission is built for Chevrolet, as an improved iteration of the 4L60E, and a successor to the 700R4. Unlike its predecessors, the 4L60E and later 4L65E is an electronic automatic transmission, with a five-pinion gearset, overdrive, and a stock torque limit of about 380 ft.-lbs. torque.

With some elbow grease, the right aftermarket parts and a good deal of experience with GM transmissions, a dedicated and qualified specialist can turn the 4L65E into a workhorse of a transmission, with a total 650 horsepower and matching 650 ft.-lbs. of torque. The 4L65E is ideal for such a high amount of torque, as its five-pinion design, 3-4 clutch and improved hydraulic fluid capacity make it a clear winner over the 4L60E for heavier builds with more required power.

But it takes more than that to justify buying a 4L65E over another transmission, or even figuring out which one you’ve currently got in your own Chevy. From the Turbo-Hydramatic 700R4, to the 4L60E, the 4L65E, and more recent 4L70E, GM has come up with several different ways to refine the design of the old-time classic TH350. However, as similar as these transmissions might be, they each come with different gear ratios, valve bodiestorque converters, and more. Some are interchangeable – others aren’t.

History of the GM 4L65E Transmission

The history of the 4L65E goes as far back as the 1960s, when General Motors introduced the Turbo-Hydramatic 350 as a new and improved automatic transmission, a successor to the Powerglide. The TH350 could be found under the hood in most GM trucks and rear-wheel drive cars up until the mid-80s, due to its reliability, sturdy build, and compact size.

While small at under 22 inches in length and roughly 120lbs in weight, it was a transmission that at the time packed enough of a punch to drive a Jeep. Typically produced without a torque controller until the TH350-C in ’79, the transmission was eventually succeeded by GM’s 700R4.

The 700R4 made the leap into the four-speed automatic transmission market, introducing overdrive as a new feature for the more fuel-conscious America of the early 80s and beyond. With fuel prices up and the automobile still in hot demand, the 700R4 allowed GM vehicles to ride more efficiently, while incorporating many of the features that made the TH350 so great, including durability and power.

While still being a non-electronic transmission, access to overdrive and general better fuel efficiency allowed the 700R4 to help GM meet stricter emission guidelines, and help save customers money on fuel costs. To this day, aftermarket modifications allow the 700R4 to act as a premium stock transmission to modify and stick into big block racing vehicles without electronic controls.

Designated as a 4L60 in the early 90s (after its 4 speeds, longitudinal positioning and 6000 lbs. GVW), the 700R4 was eventually succeeded by the 4L60E in 1997, GM’s first automatic overdrive transmission with electronic controls. Sporting the same length, weight and overall bellhousing, the main difference between the two was the introduction of electronic controls, and an adapted valve body and actuation system to accompany the new solenoids and actuators.

Different versions of the 4L60E hit the market over the course of its lifetime, differentiated through their tail housing, and presence or lack of removable bellhousing. Due to a change in solenoids and a six-bolt tail shaft, 4L60E transmissions built after 1996 are incompatible and non-interchangeable with older models.

Finally, a stronger updated version of the 4L60E was introduced in 2001 with a five-pinion planetary carrier and improved input shaft. Also sporting a different torque controller, the 4L65E comes with a hardened sun shell and has an overall better potential as a big block performance transmission due to its planetary carrier.

Specs on the 4L65E

Sporting a five-pinion planetary carrier, a 300mm input shaft over the 4L60E’s 298mm input shaft, and a better 3-4 clutch, the 4L65E comes with the following gear ratios:

  • 1st gear: 3. 06
  • 2nd gear: 1.62
  • 3rd gear: 1
  • 4th gear: 0.69

Ultimately, the upper limit for the 4L65E even with a lot of tender, loving care is 700hp – anything beyond that is better off swapping for a 4L85E, which although much stronger, is also pricier and more power-hungry.

What Sets the 4L65E Transmission Apart?

Identifying a 4L65E from other similar transmissions, such as the 4L60/700R4 and the 4L60E, takes a little practice and know-how. Despite a thicker input shaft and a different sun shell, identifying the 4L65E without opening it up requires knowledge of the alternate designations for the transmissions (M30 for the 4L60E, M32 for the 4L65E), and a few key cosmetic differences.

Older 4L60E transmissions come with a four-bolt tail housing, versus the 4L65E’s six-bolt. However, some later 4L60E transmissions also came with a six-bolt tail housing, as well as a removable bellhousing. Performance versions of the 4L60E are sometimes also designated with M32.

Ultimately, your best bet towards identifying a 4L65E is to bring it to a shop. You can check transmission codes, designations and even try and gauge the difference between input shafts, but the key differences are only visible inside the transmission.

Pushing the Limits

The beautiful thing about aftermarket parts is that even a transmission that operates on a mediocre level performance-wise can be brought up to spec with a full redo. When it comes to a custom-built 4L65E transmission, there’s a lot that can be done – from completely replacing and improving the torque converter, to installing new vanes, pump rings, thrust washers, bearings and solenoids.

Replace the input shaft, outfit the tranny with a completely revamped electronic control system and speed sensor, a custom shift kit, better cooler to prevent overheating under pressure and extra capacity pan for up to 14 quarts of transmission fluid, and you’ve got yourself a completely different piece of equipment.

Ultimately, choosing the right transmission for your car – and choosing the right set of custom modifications to said transmission – is a job in and of itself. You must consider the size and traction of your tires, the power your engine develops, the exact purpose of the car and the kind of performance you’re looking for, etc.

In some respects, a 4L60E might beat out a 4L65E simply because it happened to be what your car came with, or because you got a much better deal for it from the boneyard. Choosing between the two is a matter of circumstance, and budget. If you don’t need the extra power afforded by an extra pinion, jumping to a 4L65E might not be worth it. On the other hand, a heavier build seeking more torque and horsepower would do better with something stronger.

200-4R Transmission: The Holy Grail of Power, Fuel Efficiency

200-4R Transmission: The Holy Grail of Power, Fuel Efficiency - Gearstar Performance

If you are looking for a way to upgrade your classic muscle car’s Powerglide or TH350, then you would be hard-pressed to find a better answer than the 700R4, or the 200-4R. Yet while the 700R4 is often seen as the more popular successor to the throne of the TH350, the 700R4 is not going to squeeze into every build, not is it necessarily the best fit for your car – especially if you are going forward with a lot of aftermarket work in mind.

If you are looking for an upgrade to your old muscle car and want something that both packs a punch and substantially improves your fuel efficiency, then the 200-4R is the right place to start. Its bellhousing, drive shaft, and mechanical speedometer make it a superior fit for vintage cars, and its sturdier build and better torque capacity make it the better non-electronic 4-speed overdrive transmission for classic GM performance builds.

It is not very costly, can still be found scrap/salvage yards and in junk shops, and is reasonably affordable. And remember, if you snag yourself a late-model 200-4R from one of the more recent productions, it will handily outdo the stock 700R4 found in older vehicles.

It is by no means a perfect transmission and the 700R4 will typically outdo it, and even if you pick up a newer stock version from the wrecking yard at a bargain you will still have some ways to go to making it race-worthy, but a little magic and some elbow grease will turn the 200-4R into your personal holy grail of power and fuel efficiency.

History of the GM 200-4R Transmission

The 200-4R was a continuation of the Turbo Hydramatic line of GM transmissions, specifically being the successor of the TH200, a light-duty TH350 designed to improve fuel efficiency in the face of the oil embargo of 1973.

Years later, in 1981, the TH200 was replaced by the newly-introduced 200-4R, a 4-speed automatic overdrive transmission used in high-power GM trucks and cars, including the Buick Grand National and Pontiac Firebird Trans-Am. The 200-4R can be found in various GM B-body vehicles, C-body vehicles, G-body vehicles, and D-body vehicles.

Similar in build to the TH350, the 200-4R proved to be a great update to the outdated 3-speed transmission in builds where an overdrive gear was a must. Eventually, in 1990, the 200-4R was phased out for the 700R4, and later iterations of the same transmission including the 4L60 and 4L60-E.

Rundown on the Numbers

The 200-4R is a 4-speed automatic overdrive transmission by GM, capable of fitting into most Chevy’s from the 80s and before, built similarly to the TH200 and TH350, as well as the 2-speed Powerglide transmission. Build with a torque converter lock, a 27-spline input/output shaft, 11-quart fuel capacity, a case length of about 27” and a width of about 19”, and an aluminum outer casing, its torque capacity outdoes even the reliable 700R4 of the time. Its gear ratios are:

  • 1st gear: 2.74
  • 2nd gear: 1.57
  • 3rd gear: 1
  • 4th gear: .67

The 200-4R uses a throttle valve cable, which can be replaced based on the exact specifications and compatibility of your car. A mismatched throttle valve cable can wear the transmission out faster, so make sure your cable matches your car’s throttle bracket and carburetor.

Telling a 700R4 apart from the 200-4R is thankfully quite easy, and doesn’t require you to look under the hood. The 200-4R comes with a unique-looking 16-bolt transmission pan, much like the 700R4 and 4L60 but completely different in design. The pans on the 700R4 and 4L60 are square, whereas the 200-4R tapers off on one side. The TH350, on the other hand, looks much like the 200-4R but comes with only 13 bolts.

Because of the similarities in both the size and design of the 200-4R and the TH350, the 200-4R offers a much simpler update to a 4-speed overdrive transmission in your older car than the 700R4 does.

Why Choose the 200-4R Transmission?

The primary reason for picking a 200-4R over the 700R4 boils down to what kind of car you have, and what you are building for. The 200-4R comes with better torque capacity and is a much more straightforward fit into cars that originally sported the 3-speed TH350 or 2-speed Powerglide, but its availability and lack of durability vs. the 700R4 means it may not be a good fit for newer vehicles from the time.

The gearing on the 200-4R is also much more similar to that of the TH350, giving it another plus point as the ideal upgrade to 4-speed overdrive on older Chevy’s. For the most part, even the biggest incompatibilities would require very little modification for a bolt-in.

Versus the 700R4, the fourth gear (overdrive) is slightly more aggressive, rotating at about 3% lower RPM and thus making for a more fuel-efficient transmission. Versus later electronic models (such as the 4L60E), the 200-4R is both more affordable and simpler to work with, although concerns around the integrity of the TV cable and difficulties that often arise when trying to adjust it are always factors to take into consideration.

Of course, there are plenty of reasons to admire and pick the 700R4 over the 200-4R – if the circumstances are right. There is no definitive answer – it always depends on what you have got on-hand, and what you are aiming to accomplish. Even if the 700R4 happens to be a slightly better fit for you, you might end up saving more if you find a late-model 200-4R for a better bargain.

Modernizing the 200-4R for Better, Higher Performance

As good as a transmission can be in its pure and intended form, nothing beats what a custom build can get you. And with the right aftermarket parts and some effort from a GM transmission expert, the 200-4R can go from being an aluminum transmission straight out of the 80s, into being a 21st-century powerhouse for performance-oriented muscle cars, complete with a reliable overdrive and heavy-duty materials.

When power becomes a necessity, a customized 200-4R transmission with the appropriate torque converter can hit over 700hp and 675 ft.-lbs. torque, coming in complete with the works, from a high-capacity 30,000 GVW transmission cooler, hardened input shaft, stator shaft and bearings and rings, to a high-capacity pump assembly, 10-clutch direct drum assembly, brand new transmission pan and much more.