List of GM transmissions. General Motors (GM) is an American car manufacturing company. It manufactures its own automobile transmissions and only purchases from suppliers in individual cases. They may be used in passenger cars and SUVs, or light commercial vehicles such as vans and light trucks.

Basically there are two types of motor vehicle transmissions:
 Manual – the driver has to perform each gear change using a manually operated clutch
 Automatic – once placed in drive (or any other 'automatic' selector position), it automatically selects the gear ratio dependent on engine speed and load

Basically there are two types of engine installation:
 In the longitudinal direction, the gearbox is usually designed separately from the final drive (including the differential). The transaxle configuration combines the gearbox and final drive in one housing and is only built in individual cases
 In the transverse direction, the gearbox and final drive are very often combined in one housing due to the much more restricted space available

Every type of transmission occurs in every type of installation.

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. 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:
1937–1939 Automatic Safety Transmission (AST) — Oldsmobile, Buick in 1938 only
1940–1967 Hydramatic — 4-speed Pontiac/Oldsmobile/Cadillac (totally different design than the later Turbo-Hydramatics)
1947–1952 Dynaflow — Buick's "2-speed CVT"
1950–1973 Powerglide — 2-speed Chevrolet (also used by Pontiac, Holden, Vauxhall and Opel). 
1953-1955 Twin Turbine Dynaflow: the 1st redesign w/ 2 turbines & single stator.
1956-1957  Twin Turbine 2 Dynaflow: the 2nd redesign w/ 2 turbines & variable-pitch stator.
1956-1964 Dual-Coupling/Controlled-Coupling Hydramatic —  Substantial redesign of the Hydramatic. (Aka Cadillac 315/P315 HydraMatic, Oldsmobile Jetaway/StratoFlight, Pontiac Super HydraMatic).
1957–1961 Turboglide — Chevrolet's constant-torque "3-speed CVT" (V8 models only, except Corvette)
1958–1959 Flightpitch/Triple Turbine Dynaflow — Buick's 3rd redesign w/ Triple Turbines 
1961–1963 Buick's Dual-Path Turbine Drive
1961–1964 Roto Hydramatic — Compact Hydramatic-based 3-speed used by Oldsmobile, Pontiac, Holden, Vauxhall and Opel
1962-1972 TempestTorque — Powerglide-based 2-speed with "Split-Torque".
1964–1969 Super Turbine 300 — 2-speed (aka Buick ST-300, Oldsmobile Jetaway, Pontiac "Automatic")
1968–1971 Torque-Drive — Chevrolet's column-shifted 2-speed semi-automatic Powerglide (only w/ 6-cyl)

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

1964–1992 Super Turbine 400/TH400/3L80
1969–1986 TH350/TH350C/TH375B/TH250/TH250C
1972–1976 TH375 — Light duty version of TH400
1976–1987 TH200/TH200C
1981–1990 TH200-4R
1982–1993 TH700R4/4L60
Heavy-duty rear wheel drive
1971–1994 3L80HD (heavy duty version of TH400)
Light-duty rear wheel drive
1969–1998 TH180/TH180C/3L30 — European/Asian model. Used/manufactured by Holden as the Trimatic.
Longitudinal front wheel drive
1966–1978 TH425 — 3-speed
1979–1981 TH325 — 3-speed
1982–1985 TH325-4L — 4-speed
Transverse front wheel drive
1980–1999 TH125/TH125C/3T40 — 3-speed light-duty
1984–1994 TH440-T4/4T60 — 4-speed medium-duty

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)

1991–2001 4L30-E — 4-speed light-duty (used in BMW, Cadillac, Isuzu, and Opel cars)
1992– 4L60-E/4L65-E — 4-speed medium-duty (used in GM trucks and rear-wheel-drive cars)
1991– 4L80-E/4L85-E — 4-speed heavy-duty (used in GM trucks)

First-generation transverse (Front Wheel drive)

1995–2010 4T40-E/4T45-E — 4-speed light-duty (used in smaller front wheel drive GM vehicles)
1991–2010 4T60-E/4T65-E/4T65E-HD — 4-speed medium-duty (used in larger front wheel drive GM vehicles)
1993–2010 4T80-E — 4-speed heavy-duty (used in large FWD GM vehicles, only with Cadillac NorthStar V8 and Related Oldsmobile V8)

Second-generation longitudinal (Rear Wheel drive)

2000–2007 5L40-E/5L50 — 5-speed medium-duty (used in Cadillac's Sigma vehicles)
2006–present 6L45 · 6L50 — 6-speed medium-duty (used in GM Sigma platform cars)
2005–present 6L80 · 6L90 — 6-speed heavy-duty (used in GM trucks and performance cars)
2014–present 8L 90 — 8-speed heavy-duty (used in GM trucks and performance cars)
2016–present 8L 45 — 8-speed light-duty (used in GM luxury cars)
2017–present 10L80 — Ford-GM 10-speed automatic (used in GM light trucks pickups and related SUVs)
2017–present 10L90 — Ford-GM 10-speed automatic (used in GM performance cars) 

Second-generation transverse (Front Wheel drive)

2008–present 6T30/6T40/6T45 — 6-speed light-duty
2006–present 6T70/6T75 — 6-speed medium-duty
2016–present 9T50/9T65 Hydra-Matic – 9-speed

Hybrid and PHEV

2ML70 / AHS-2 - Two-Mode Hybrid transmission (RWD)
2MT70 - Two-Mode Hybrid transaxle (FWD, Saturn Vue Hybrid)
4ET50 (MKA) - Voltec Electric Drive Unit Transaxle (Chevrolet Volt (first generation))
4ET55 (MKD) - Voltec Electric Drive Unit Transaxle (Cadillac ELR)
5ET50 (MKV) - Electronically controlled, continuously variable automatic transaxle (Chevrolet Volt (second generation))
5ET50 (MKE) - Electronically controlled, continuously variable automatic transaxle (Full Hybrid, Ninth Generation Chevrolet Malibu)
4EL70 (MRD) - Electric Drive Unit Transmission (Cadillac CT6 PHEV)

Other automatics

Aisin AF33 — 5-speed transverse automatic made by Aisin AW Co., Ltd.
Allison 1000 Series — 6-speed longitudinal automatic made by Allison Transmission
Saturn MP6/MP7 — 4-speed automatic developed by Saturn for use in the S-series from 1991 to 2002
VTi transmission — continuously variable transmission
Tremec M1L transmission — 8-speed Dual-Clutch made by Tremec for the Chevrolet Corvette C8
GM  VT40/CVT-250 (RPO MRG) Introduced in 2019 — continuously variable transmission

Manual transmissions

Longitudinal transmissions

Aisin AR5/MA5 — 5-speed longitudinal manual made by Aisin
Aisin AY6 — 6-speed longitudinal manual made by Aisin
Getrag 260 — 5-speed longitudinal manual made by Getrag
Muncie M20 — 4-speed longitudinal wide ratio manual transmission made by GM at their Muncie, Indiana factory
Muncie M21 — 4-speed longitudinal narrow ratio manual transmission made by GM at their Muncie, Indiana factory
Muncie M22 — 4-speed longitudinal heavy duty narrow ratio manual transmission made by GM at their Muncie, Indiana factory
Saginaw M26/27 transmission — 3 and 4-speed longitudinal light duty (less than 300 hp) wide ratio manual transmission made by GM at their Saginaw, Michigan factory
Muncie M62/M64 — 3-speed longitudinal transmission made by GM
Muncie SM318 transmission — 3-speed transmission used from 1954 through 1969 in both passenger car and truck applications. Also found in wide and narrow ratio configurations.
Muncie SM319 transmission — 3-speed transmission physically identical to the Muncie SM318, with an added Borg Warner overdrive unit.
Muncie SM420 transmission — 4-speed manual used up to 1967, very similar to sm 465 except small changes to gear ratios and location of reverse. 
New Process Gear NP435 - 4-speed longitudinal transmission used in a select handful of 67-72 GM pickups
New Process Gear A833 RPO MY6 or MM7 — 4-speed longitudinal A833 overdrive transmission made by New Process Gear for early to mid 1980s General Motors Light Trucks
Muncie SM465 — 4-speed longitudinal manual used in 68- 91 Chevy 1/2 3/4 and 1 ton trucks
New Venture Gear NV1500 — 5-speed longitudinal manual made by New Venture Gear
New Venture Gear 3500/4500 — 5-speed longitudinal manual made by New Venture Gear
Borg-Warner T-10 transmission — 4-speed longitudinal manual currently made by Richmond Gear; originally made by Borg-Warner
Tremec T-5 — 5-speed longitudinal manual currently made by Tremec; originally made by Borg-Warner
Borg-Warner R-10 overdrive - 3-speed manual transmission with electric overdrive used 1937-1964
Borg-Warner R-11 overdrive - 3-speed manual transmission with electric overdrive Ford used them up until 1975 in trucks.
Borg-Warner T-50 transmission — 5-speed longitudinal manual - used by GM in its RWD H-Body cars and a few other limited light duty applications from 1976 to 1978;
Tremec T-56 — 6-speed longitudinal manual overdrive made by Tremec; formerly made by Borg-Warner
Tremec TR-6060 — 6-speed longitudinal manual overdrive made by Tremec
ZF S6-650 — 6-speed longitudinal manual made by ZF Friedrichshafen
Tremec TR-6070 — 7-speed longitudinal manual overdrive made by Tremec

Transverse Transmissions

F23 — 5-speed transverse manual manufactured by Getrag
F25 — 5-speed transverse manual manufactured by Getrag
M17 — 4-speed transverse manual manufactured by Muncie
F35 — 5-speed transverse manual manufactured by Saab in Gothenburg, Sweden
F40 — 6-speed transverse manual manufactured by FGP Germany
Getrag 282 — 5-speed transverse manual designed by Getrag and manufactured by Muncie Getrag
Getrag 284 — 5-speed transverse manual designed by Getrag and manufactured by Muncie Getrag
M32 — 6-speed transverse manual manufactured by Fiat-GM Powertrain in Turin, Italy since 2004
MP2/MP3 — 5-speed manual developed by Saturn for use in the S-Series from 1991 to 2002

References

Opel
GM transmissions