Reading the hollender I got , comes up :
Case #3845121 ( Cast. #3845122) Pass. (exc. O.D.&57 close ratio); corvette 55-56 also list 3707166 with this case # cast # as 55-59 1/2ton-1ton Pass. with out OD,plus several other applications for that case, Just a guess, but it's 55-57 Pass. sedan del.3 speed, 1/2 ton to 1 ton 55 - 59 3 speed, that case was used in 60 - 63 10 and 20 chevy also, should be another 7 didget number to id trans, best I can do , hope It helps,
Jbennett
40 burb
