1968 - 1970 Muncie Four Speed Transmission Main Case GM 3925660 : M-20, M-21, M-22

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 3925660 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. This is a licensed GM restoration part.

NOTE ~ This is only correct for 1968 - 1970 Muncie M-20, M-21, and M-22.

*These main cases are finished by hand. There will be grind marks, burr marks, and imperfections. There will be very minor size differences in hole openings, etc. But once assembled, installed and dressed, they work great! Nice used have gotten basically impossible. Overall These main cases are a Blessing.

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

PART NUMBER: TRA-610A