Firebird Central | 1970 - 1974 Firebird Muncie Transmission Case GM 3925661: M-20, M-21, M-22, Buy Yours Today!

1970 - 1974 Firebird Four Speed Muncie Transmission Main Case GM 3925661; M-20, M-21, M-22

New four speed Muncie Transmission main case for your 1970 - 1974 Firebird or Trans Am. You can now replace your damaged or broken M-20, M-21, or M-22 transmission main case with this new OEM style factory replacement. This case has correct part number 3925661 with U.S. PATENT number 3088336 and GENERAL MOTORS CORP castings. Both fill and drain plugs are drilled and tapped. Lower cluster gear countershaft pin hole is one inch in diameter. Exact shape, size, and details. Stop trying to look for one with good threads and no broken ears,,, here it is!! This is a licensed GM restoration part.

NOTE ~ This is only correct for 1970 - 1974 Muncie 4 Speed M-20, M-21, and M-22.

*These main cases are finished by hand. There will be grind marks, burr marks, and imperfections. When installed and dressed, they look great. Nice used have gotten basically impossible. Overall These main cases are a Blessing.

*These main cases are the correct shape and size. Make sure this is the main case you need and want as they are non-refundable for any reason.

PART NUMBER: TRA-610B