Why is AA used on engine number

Don/WI

Senior Member
Why do they use the AA on the engine number of 1 ton trucks when the engines are all the same? Don/WI
 
Because they really werent all the same -

AA trucks had a check valve ball setup for the rear main oil return tube so when they were tilted to unload grain all the oil didnt run out.

Also had a slightly heavier clutch and slightly larger clutch to move the 1.5+ tons that could be on it.
 
Wasn't there a difference in bell housing, too? I know that H.A.M.B. hotrodders covet that bell housing so that it can accept late model Ford truck transmissions.
 
Wasn't there a difference in bell housing, too? I know that H.A.M.B. hotrodders covet that bell housing so that it can accept late model Ford truck transmissions.

Yes for very late 1929-31, but it was the clutch springs that determined the engine number prefix.

Bob
 
The AA trucks with the 4 speed transmission had the pedal shaft on the transmission case not the bell housing. They were shallower than a regular bell housing so lent themselves to transmission conversion .

John in windy rainy Suffolk County England .
 
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