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 4L70EGM’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 StatsThe 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