1965 vin# 2528-I have your m-21 trans!

[Bill C.]

Hi,
Tripped onto this excellent used M-21 close ratio muncie with an assembly date of P0916 out of car # 2528. Is the car out there?
PM me!

[Wayne M.]

Re: 1965 vin# 2528-I have your m-21 trans!

Bill --- just curious; does it have a circular grind on the rear edge of the maincase before Muncie stamped the assembly date, like the pic on mine, below ?

[Bill C.]

Re: 1965 vin# 2528-I have your m-21 trans!

Wayne,
Yes, it looks just like that, guess some high end "uncertified" stamper put the wrong dates or where they leftovers from a previous days work and they got ahead of themselves? I have seen this before on other dates also. Whats your take on it?
Bill Caldwell

[John H.]

Re: 1965 vin# 2528-I have your m-21 trans!

Bill -

I've seen a number of Muncies with EXACTLY the same grind mark and hand-stamp pattern in the Camaro side of my hobby; guys who rebuild Muncies for a living say that's a typical Muncie in-plant grind-out and repair re-stamp, not uncommon in the 60's.

[Wayne M.]

Re: 1965 vin# 2528-I have your m-21 trans!

Bill C. and John H. --- Here's my "take" on these Muncie assembly date grinds: it was STANDARD PRACTICE early in the 1965 model year . To conform with Chevrolet instructions to move from the lower driver side cover corner (a machined flat surface) to the passenger side, some order must have been issued to machine the rough cast surface before applying the date stamp.

Since my car had (what I thought was) this anomaly, I started collecting photos off eBay and elsewhere (I have at least 30). Result: the earliest grind is P0806 (probably the day SOP began for 1965 model year transmissions) and goes to P0916 -- there's a couple with this date and the grind [mine, Bill's and a few others], but surprisingly ONE case WITHOUT grind on 16 Sept 1964. No trannys before P0916 were without the grind prep. After that, my data bank contains a P0923 without grind --- wasn't really interested if they didn't have it , leading me to conclude that during some shift on Sept 16th, the order came down to stop the grind step before stamping the assembly date.