Originally Posted by jorb
Originally Posted by Whitelightning
How come the 3:55 ring gear set won't work with a 1954 housing??
John
One other thing the 3.55 ring gear will not work on the 1954 1/2 ton differential/spool case.
So that the ring gear bolt pattern lines up with the bolt pattern on the differential/spool case.
Correction: The 3.55 ring gear will bolt on to the 1954 differential/spool case,
but the 3.55 ring & pinion gears are larger. Because of the larger gear size,

Thanks, in other words the spool is different between the 4:11 and the 3.90 ring gears.

John
there is not enough room for adjustment using the 1954 differential/spool case.
The 1954 differential/spool case was designed for the smaller size 3.90 ring & pinion gears.

You have to use the 4.11, 1940 to 1953 Chevy 1/2 ton differential/spool case. part number 3652336.
Master parts Cat picture. Group # 5.510 MPC Part #3652336
MPC also indicates the 55-57 1/2 ton O/D.

You retain the spider gears from inside the 1954 differential case
to use inside the 4.11, 1940 to 1953 Chevy 1/2 ton differential/spool case.

All you are using is the 4.11, 1940 to 1953 Chevy 1/2 ton differential/spool case.
Everything else gets transferred over.