1965 Chevy Truck Manual Transmission Identificationby Floyd Drake III
Chevrolet trucks made in 1965 are equipped with one of three manual transmissions: Muncie, Saginaw and Borg-Warner. The first two were manufactured by General Motor, the third, Borg-Warner. Visual identification, model number and gear-tooth counting provides the surest identification.
To visually identify a transmission, count the number of bolts on the cover, and locate the reverse gear lever. The Muncie has seven bolts, and the reverse lever is in the extension housing. Saginaw transmissions also have seven bolts, but the reverse lever is on the cover. Borg-Warner transmissions have a nine-bolt cover.
Due to inconsistencies, the reliability of the Chevrolet manual transmission numbering system is questionable. The code, a combination of numbers and letters, will be stamped somewhere on the gear box. To decode the number, consulting a reference table is suggested. (see Reference 2)
Muncie Gear Teeth
To reliably identify the different models within the Muncie group, Input gear-teeth should be counted. The Muncie M20 has 24 teeth, while the M21 and M22 have 26 teeth. The M22 had "straight cut" gears, whereas the M21 gear teeth have a higher pitch angle. The M22 is also a much louder transmission that is normally installed behind big-block engines.