I found a muncie with the main body casting number of 3925660 and the tail shaft number of 3857584. It has 2 grooves on the input shaft(10 spline). I understand that the m22 didn't have any grooves on the input shaft. I haven't seen the gears inside but would this be a M22??? Thanks
The M-22 had no rings, the early M-20 had no rings either. The 2 rings were 66-70 M-20. But the casting # you have is normally associated with M-22, I would look inside to check further.
In the book I have, Chevrolet by the Numbers, the 65 to part way through 70 M-22 had 10 teeth input and 27 output. Then some 70 through 72 had 26 in and 32 out. This says the M-22 was manufactured in 73 & 74 for other GM divisions and Chevrolet service applications. All I have.
The 3925660 main case was used 1968,1969 and the first part of the 1970 model year for M-20's, M-21's, and M-22's... If your trans has 2 grooves around the input splines theres a good chance its and M-20 Hope this helps... Crash
