AA and BB 4 speed differences

[JON]

Can someone tell me all the differences between an AA 4-speed tranny and a BB 4-speed tranny if there are any? Can I use a BB trany on my 29 AA doodlebug? Thanks

[Downunder Rob]

Jon
as far as i am aware the only major difference is that the AA box has the pivot shaft coming out of the side for the pedals to mount on

[E.Moore]

The AA 4 speed transmission case has raised letters AA 7006, the later cases do not have those raised letters. The internal parts are interchangeable from 1929 to 1948. The bell housing is different from the AA/BB, but are interchangeable. The clutch pivot arm on the AA is much shorter than the BB. The BB pivot arm would allow for less pedal pressure to engage the clutch.

[Brady]

I have a '48 (?) 4 speed, with the e brake at the rear. Would this gear box bolt up to the AA clutch housing, and work OK for the clutch assy and the pilot bearing areas? It isn't intended to be a restoration or driver- just a doodlebug... Thanks for any and all assistance, FB

[E.Moore]

The AA Transmission is basically the same through 48, so you should be able to bolt the AA bell housing to the 48 transmission and use it on an A/AA doodlebug.

[JON]

Many thanks to all of you that have replied to my inquiry. I ended up getting another AA tranny for my doodlebug. Jon