C3 Transmission ID

[Norm C.]

Taking inventory on part #'s and Date Codes. What are the transmission numbers and codes to look for on a 72 Coupe SB 4-speed? Where exactly can they be located on the transmission?

Thanks in advance for the help!!!

[Jim T.]

Re: C3 Transmission ID

Your Muncie date code location ison the right side of the maincase, just in front of the extension housing. You should find a "P2" followed by a letter to identify the month and two numbers to identify the day. The last stamping letter will be either an A or B. The A identifies the M20 Muncie and B would identify the M21. The M20 is the standard ratio and the M21 is the close ratio Muncie 4 speed. It could be a C, however only 20 1972 Corvettes left the factory with a M22 close ratio. "P 2 A 15 A" would identify a Muncie 4-speed 1972 January 15th with wide ratio gears.

[Warren F.]

Re: C3 Transmission ID

Norm,

You should also find a small retangular metal tag on the drivers side, attached to one of the side cover bolts. This tag should read something like 7 numeric digits followed by 2 alpha letter characters, ie: 3975533WO as an example. This tag is different depending on M20, M21 or M22.

[John H.]

Re: C3 Transmission ID

If the transmission is original to the car, it will also have a derivative of the VIN number stamped vertically on the main case rib rearward of the side cover.