GM Muncie M21 is a manual gearbox from GM Muncie.
Buick
| Vehicle | Years | Shift pattern | Gearbox source | Members |
|---|---|---|---|---|
| Buick Skylark / Gran Sport (GS) A-body 4-speed [1]Applies to: 1966-1970 | 1964-1972 | 4 speed, reverse top left | Corroborated | |
| Buick Skylark / Sportwagon A-body 3-speed and 4-speed manuals [citation needed] | 1971 | 4 speed, reverse top left | Lead | |
| Buick Special A-body (GM) 4-speed manual cars [2] | 1967-1970 | 4 speed, reverse top left | Corroborated |
Chevrolet
| Vehicle | Years | Shift pattern | Gearbox source | Members |
|---|---|---|---|---|
| Chevrolet Bel Air Full-size 4-speed floor shift [citation needed] | 1968-1969 | 4 speed, reverse top left | Lead | |
| Chevrolet Biscayne Full-size 4-speed floor shift [citation needed] | 1968-1969 | 4 speed, reverse top left | Lead | |
| Chevrolet Camaro First generation Base, RS, SS, Z28 with 4-speed [3]Applies to: Base, RS, SS, Z28 with 4-speed | 1967-1970 | 4 speed, reverse top left | Corroborated | |
| Chevrolet Camaro First/second generation 4-speed [4] | 1971 | 4 speed, reverse top left | Corroborated | |
| Chevrolet Camaro First generation 4-speed [5] | 1972-1973 | 4 speed, reverse top left | Corroborated | |
| Chevrolet Caprice Full-size 4-speed floor shift [citation needed] | 1968-1969 | 4 speed, reverse top left | Lead | |
| Chevrolet Chevelle A-body (GM) 4-speed cars (listing excludes 1970 with 454) [6]Applies to: All (Muncie) | 1965-1970 | 4 speed, reverse top left | Corroborated | |
| Chevrolet Corvette C2 / C3 4-speed manual [7] | 1964-1970 | 4 speed, reverse top left | Corroborated | |
| Chevrolet Corvette C1 / C2 / C3 4-speed manual [8]Applies to: All (Muncie) | 1971-1974 | 4 speed, reverse top left | Corroborated | |
| Chevrolet El Camino 4-speed [9] | 1968-1971 | 4 speed, reverse top left | Corroborated | |
| Chevrolet Impala Full-size 4-speed manual [10][citation needed]Applies to: 1966-1969; 1963-1965 | 1963-1969 | 4 speed, reverse top left | Lead | |
| Chevrolet Nova Third generation 4-speed manual [citation needed] | 1971 | 4 speed, reverse top left | Lead | |
| Chevrolet Nova (Chevy II) Chevy II / Nova 4-speed manual [11]Applies to: M20/M21/M22 (Muncie) | 1965-1970 | 4 speed, reverse top left | Corroborated |
Chevrolet / Pontiac / Oldsmobile / Buick
| Vehicle | Years | Shift pattern | Gearbox source | Members |
|---|---|---|---|---|
| Chevrolet / Pontiac / Oldsmobile / Buick Muncie M20 / M21 / M22 (cars, some trucks) Corvette, Camaro, Chevelle, Nova and others Close/wide-ratio 4-speed with synchronised 1st and reverse [12] | pre-1970s to 1970s | 4 speed, reverse top left | Corroborated |
Oldsmobile
| Vehicle | Years | Shift pattern | Gearbox source | Members |
|---|---|---|---|---|
| Oldsmobile Cutlass / F-85 A-body (GM) 4-speed manual [13] | 1965-1970 | 4 speed, reverse top left | Corroborated |
Pontiac
| Vehicle | Years | Shift pattern | Gearbox source | Members |
|---|---|---|---|---|
| Pontiac Firebird First generation 4-speed manual [14]Applies to: V8 cars | 1967-1970 | 4 speed, reverse top left | Corroborated | |
| Pontiac Firebird / GTO / LeMans 4-speed [15] | 1969-1971 | 4 speed, reverse top left | Corroborated | |
| Pontiac Grand Prix Second generation 4-speed manual [citation needed] | 1969-1970 | 4 speed, reverse top left | Lead | |
| Pontiac Tempest (incl. LeMans/GTO) A-body (GM) 4-speed manual [16] | 1964-1970 | 4 speed, reverse top left | Corroborated |
Research notes
Caveats and conflicts (21)
- Buick not individually broken out; 1964-65 and 1971-72 not shown (Wikipedia Skylark says 1963 Special/Skylark used a floor-shift Borg-Warner T-10).
- No 1971 Buick source names the gearbox. Saginaw 4-speed also existed in non-performance GM cars from 1966 (chevellestuff.net).
- Special/Skylark share the A-body; Special not named in the fitment text. 1967 is in range.
- Bel Air/Biscayne/Caprice are not named in any source opened. chevellestuff.net notes Saginaw wide-ratio 4-speeds appear from about Feb/Mar 1966, so the Muncie assumption may be wrong for non-performance cars.
- M22 availability by year not shown for Camaro here. A Saginaw 4-speed was also available on some 1967-69 Camaros per general sources (not opened).
- Model codes by year not shown.
- Row says First generation but 1972-73 cars are second generation. M22 is listed only through 1972 on Corvette; Camaro not checked.
- Retail/parts reference, not OEM. M22 listed on the 1965-1970 table except the 454.
- 1963 early cars used Borg-Warner T-10 then M20 (not in row). Wikipedia Muncie page lists Corvette 1963-1974.
- Enthusiast reference, not OEM.
- El Camino shared the Chevelle drivetrain; El Camino not itemized.
- Saginaw 4-speed also possible from 1966 per chevellestuff.net.
References
- Retailer. OER fitment: '1966-70 Various GM Vehicles Including Impala, GTO, Skylark Models; Rebuild Kit; Muncie 4 Speed; M20, M21, M22'. [link]
- Retailer. OER fitment: '1966-70 Various GM Vehicles Including Impala, GTO, Skylark Models; Muncie 4 Speed; M20, M21, M22'. [link]
- Wikipedia. Wikipedia Muncie page applications list: 'Chevrolet Camaro: 1967 to 1973'; Wikipedia Camaro: Z/28 'backed by Muncie manual four-speed'. [link]
- Wikipedia. Wikipedia Muncie page applications list: 'Chevrolet Camaro: 1967 to 1973'. [link]
- Wikipedia. Wikipedia Muncie page applications list: 'Chevrolet Camaro: 1967 to 1973'. Corvette table (corvetteactioncenter.com) shows only M20/M21 in 1973-74. [link]
- Retailer. chevellestuff.net: M20 wide-ratio 1963-1975, M21 close-ratio 1964-1975, M22 1967-72 with M22 input shaft table 1965-1970. [link]
- Wikipedia. Wikipedia Corvette C2: in 1964 'the two Borg-Warner T-10 four-speeds gave way to a similar pair of gearboxes built at GM's Muncie'; chevyhardcore: M22 'starting with the 1965 Corvette'. [link]
- Retailer. corvetteactioncenter.com C3 transmission tables: 1971 and 1972 list M20, M21 and M22; 1973 and 1974 list M20 and M21 only. [link]
- Retailer. chevellestuff.net page title 1964-1972 Chevelle/El Camino Muncie 4-speed casting numbers and applications. [link]
- Retailer. OER fitment: '1966-70 Various GM Vehicles Including Impala ...; Muncie 4 Speed; M20, M21, M22'. [link]
- Wikipedia. Wikipedia Nova: 1968 Nova SS big-block with 'the M-21 close-ratio four-speed manual, the heavy-duty M-22 Rock Crusher four-speed'. [link]
- Wikipedia. Wikipedia List of GM transmissions: 'Muncie M20/M21/M22 - 4-speed longitudinal manual transmissions made by GM at their Muncie, Indiana factory, 1963-1975'. [link]
- Retailer. wilsonauto.com: Muncie plant 'would go on to supply driveline components such as transmissions ... for Chevrolet, Pontiac, Oldsmobile, Buick, and GMC'; chevellestuff.net lists a Pontiac and Oldsmobile long tail housing. [link]
- Forum. firstgenfirebird.org FAQ: 'In first-gens, V-8s used Muncies and OHC-6 (1- and 4-bbl) used Saginaws'; names M-20, M-21, M-22 and says the M-22 was not installed in early Firebirds. [link]
- Retailer. OER fitment: '1966-70 Various GM Vehicles Including Impala, GTO, Skylark Models; Muncie 4 Speed; M20, M21, M22'; Wikipedia Muncie lists Firebird 1967-1973. [link]
- Retailer. OER fitment: '1966-70 Various GM Vehicles Including Impala, GTO, Skylark Models; Muncie 4 Speed; M20, M21, M22'; wilsonauto.com lists GTOs among the cars where the M21 was commonly found. [link]
Categories: Gearboxes | GM Muncie
This page was last edited on November 11, 2026. Gearbox codes change by year, engine and market. Send a correction.