I looked for the trans code on my '69 4 spd and all I found was "000 35801" running vertical where I was showed in photos to look. Was does this mean? No "M" anywhere. GM patent#3088336, above that is "3925660" which is the same number I've seen in photos of M22's. There is also a large "7" then a space & an "8". I'm confusedddd!!Please HELP.

You've got the right case. Now, what's in the case is really hard to tell.

The trans code is usually painted on the main case. There is also a metal tag with the part number.

That case number is all 68-70 Output shaft will have 1, 2 or no rings. That case number was used on all M20, 21 and 22 trans from 68-70.

1 ring M-21, two, M-20, no rings M-22. That is if all original and my memory serves well.

Year 1966-1970 Type: M20 Rings: Two Spline: 10 Tooth Count: 21


Year 1963-1970 Type: M21 Rings: One Spline: 10 Tooth Count: 26

Year 1969-1974 Type: M22 Rings: None Spline: 26 Tooth Count: 26

www.gearzone.not

So you do not get confused.

PM me if you want a number to talk to a guy who has rebuilt Muncies since 65.

Thanks alot! I've learned more about my car in the last week than I ever did over the past 22 years I've owned it. Thanks again this web site "Builds Excitement".