List of GM transmissions explained

This is a list of most transmissions produced or used in General Motors (GM) vehicles.

Automatic transmissions

Early models

GM's Automatic Safety Transmission (AST) was a semi-automatic transmission released in 1937. The first mass-produced fully-automatic transmission developed for passenger automobile use was the GM Hydramatic introduced in 1940.[1] The Hydramatic was a big success, and had been installed in the majority of GM models by 1950. Throughout the 1950s, all GM Marques continued developing automatic transmission designs, both jointly and independently. Early models included:

Turbo-Hydramatic 3-speed Automatics

Introduced in 1964, Turbo-Hydramatic use quickly spread across all GM divisions, and they became referred to simply as Hydramatics (like GM's original automatic of totally different design), except for the Super Turbine 400 model. By the 1970s, Turbo-Hydramatic variants had replaced all of GM's early automatic transmission designs. In Argentina, the Turbo Hydra-Matic was marketed as the "Chevromatic" in the 1970s. Starting in the early 1980s, the Turbo-Hydramatic was gradually supplanted by four-speed automatics, some of which continue to use the "Hydramatic" trade name.

Originally a medium-duty longitudinal rear-wheel drive design, other variants were later developed, including both light-duty and heavy-duty RWD versions, and both longitudinal and transverse front-wheel drive versions.

Medium-duty rear wheel drive
Heavy-duty rear wheel drive
Light-duty rear wheel drive
Longitudinal front wheel drive
Transverse front wheel drive

Turbo-Hydramatic Model Designations

Initially, models were designated with the letters TH/THM/ST followed by the series/version number. In 1987, GM switched to a simpler naming scheme for their transmissions (Example: 4L80E)

Electronic Hydra-Matics

The next-generation transmissions, introduced in the early 1990s, were the electronic Hydra-Matics, still based on the Turbo-Hydramatic design. Most early electronic transmissions use the "-E" designator to differentiate them from their non-electronic cousins, but this has been dropped on transmissions with no mechanical version like the new GM 6L transmission.

First-generation longitudinal (Rear Wheel drive)
First-generation transverse (Front Wheel drive)
Second-generation longitudinal (Rear Wheel drive)
Second-generation transverse (Front Wheel drive)

Hybrid and PHEV

Other automatics

Manual transmissions

Longitudinal transmissions

Transverse Transmissions

Notes and References

  1. Web site: Hydra-Matic History: The First Automatic Transmission . Ate Up With Motor . 2010-05-29 . 2014-01-15.
  2. News: Panait . Mircea . GM Hydra-Matic 9T50 Transmission Confirmed for Chevrolet Cruze, Malibu, Equinox . autoevolution . 2016-12-07.
  3. Web site: GM Service Insights, pg 23 . 2019-07-16 . https://web.archive.org/web/20190109210903/https://gmserviceinsights.com/wp-content/uploads/2016/09/Service-Insights-Vol-3-2016.pdf . 2019-01-09 . dead .
  4. Web site: GM Service Insights, pg 23 . 2019-07-16 . https://web.archive.org/web/20190109210903/https://gmserviceinsights.com/wp-content/uploads/2016/09/Service-Insights-Vol-3-2016.pdf . 2019-01-09 . dead .