69 Tranny ID

[John A.]

Need some help IDing to following 4spd transmission with number combo...

Case - 3925660 -
VIN 19S700305 - P9M16 production code (no suffix letter ???)

The judging guide indicates that the M indicates an August production... which makes since for a September production month car... #305.. (correct me if I'm guessng wrong;-))
.. so, why no suffix...??? Can I determine if it is a M21 or M22 witout pulling the side cover and looking at the gears?

Thanks

[Jim T.]

Re: 69 Tranny ID

M22 will have a drain plug at the bottom right side, the M20 and M21 do not until 1970, then all Muncies had drain plugs according to Alan Colvin's book 65-69 Chevrolet by the numbers. If your transmission is out of the car you can identify it by cut rings around the input shaft or the lack of any cut rings. If it has one cut ring it is a M21 close ratio, two cut rings a M20 wide ratio, and no cut rings a M22. Also as per Alan Colvin's book, on October 21,1968 (1969 model year) a suffix letter was added to the Assembly Date Code on each Muncie transmission.
If you have a M20 you have a lower first gear which permits easier takeoffs especially when on a incline and at a complete stop. Best transmission of the three for city driving. I say this because I have a M21.

[John A.]

Re: 69 Tranny ID

Jim,

The tranny is still in the car... and it does have a drain plug on the lower right side. Sounds like M22... Any other tell-tail signs to confirm M22 while still in the car? Thanks, John

[John H.]

Re: 69 Tranny ID

John -

It will be quite noisy (gear whine) in 1st, 2nd, and 3rd gear compared to an M-20/M-21 due to the shallow helix angle of the indirect gears.