Tuning the TH700 can be time consuming and difficult to get right especially when pairing various different engines with the transmission. An external cooler might be necessary depending on climate and use of the transmission. The TH700 heats up quickly under high torque requirements and this hurts its life expectancy. The oil pump was upgraded from a 7-vane design to 10-vanes, and better pump rings and seals were used for improved reliability. Other than the input shaft, the TH700 underwent several other changes from 1984 to 1987. If your engine has been upgraded or tuned in any way, you can look at upgrading to a stronger aftermarket hardened steel input shaft to handle more torque. GM upgraded the input shaft to a 30-spline shaft within a few years of release, which helped prevent its failure. The original 27-spline input shaft that came on the earliest models was a common failure point, especially under high torque applications. We’ll go over some common issues that were seen in early models and their subsequent solutions. However, General Motors did take it onto themselves to constantly upgrade this transmission and solve its issues. Initially when the TH700 was released, reliability of the transmissions wasn’t very good. Compared to other GM transmissions of the time like the TH350, the TH700 is a much more practical transmission for daily driving. Overall, many users praise the good launch from standstill and its smooth shifts between gears. This reduces engine rpms even further and subsequently keeps the transmission cooler, helping save fuel, reduce noise and engine/transmission wear. On top of that, the torque converter clutch (TCC) can lock up which provides a direct drive from the engine to the drivetrain. The extra overdrive gear, with the 0.70 ratio leads to a 30% drop in engine rpm when it gets engaged at cruising speeds. The creation of the TH700 was the foundation of the 4L60 which ended up becoming one of the most successful transmissions in America due to its good drivability, reliability and fuel economy at the time. If built properly with upgraded internals, it can handle over and above 450 ft-lb of input torque.įrom its release in 1982, it gradually got better with internal improvements over the years until it was subsequently replaced by the 4L60 in 1990. ![]() The TH700 is a light duty transmission rated to handle about 350 ft-lb of input torque. It is considered to be one of the best and most successful transmissions of its time. Developing the TH700 evolved into the 4L60 which ended up being manufactured for over 30 years after the release of the initial TH700. GM’s decision to work on improving the transmission paid off well. These changes brought about very poor performance which wasn’t very well received. Emission standards were also getting stricter and this led car manufacturers down the route of using smaller displacement engines and a lower axle ratio. The TH700 was introduced at a time when oil prices were reaching record highs in the early eighties. It was a big upgrade from the GM TH350 transmission and the first in a new series of overdrive automatic transmissions. In 1982 General Motors released the Turbo-Hydramatic 700 automatic transmission (also called the TH700 or 700R4).
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