Visual 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.
  
  

Number Identification

• 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.