Original Poster: pedalpusher60
"My question is can I leave my rear end in place minus the torque tube assy,
and replace it with the 56 rear end guts to make it an open driveline?"

Read this POST
He says a 59 pumpkin will fit in the housing.
I'm not sure if a 56 pumpkin will also fit.
You can use the same spring but you have to flip them. Click here

But if I were you I would keep the original torque tube and axle.
Take the $800 bucks put a high speed 3.55 ring & pinion gear set $450.00 in it
and a complete rebuild kit $367.48 in the original torque tube and axle. Click here
The rebuild kit includes the Okie bushing Sleeve Assembly
You can buy it from these GUYS
That should fix any noise you have.
Unless your u-joint is the noise maker. but that's a easy fix.

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,
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.

1954 Chevrolet 3105 Deluxe Panel Truck
w/Factory HYDRA-MATIC