Like everyone has said its a 4 speed M-22 Muncie, the 22 means that the splines on the input shaft in the trans that slides into the clutch has 22 slots in the shaft. Not for a automatic, its a manual transmission
The Rock crusher was the M-22 Muncie close ratio 4 speed transmission favored in the '60's GM hot rods.Well balanced, smooth shifting and after '60 Aluminum cased capable of a lot of HP.
Rock Crusher Transmission
as stated its not an automatic, gm used those transmission in a lot of vehicles,it was the m-22 or muncie four speed tranny which was used in everything from chevelle, SS,cars to impala SS cars,even some of the vega transmissions was m-22,s, they was very popular back in the 60,s and 70,s,the reason they got the name rock crusher, was when you shifted them they sounded like that they was grinding together,they were really tough old transmissions though,i still own one in an old chevy i have,and to this day its never been rebuilt and i have owned it for over 30 years,good luck.
