Rear Axle: What is this rear end? R3? 4.27 gears

[studefan]

I have a rear end that is pretty beefy. The tag says the ratio is 4.27. 45C. Twin Traction. The tubes are larger than typical at 2 3/4 inch diameter vs the usual 2 1/2 inch. The axle shafts are larger also at 1.37 in diameter vs the 1.25 in. There is a tab with a hole welded on each tube (for a traction bar?).

It is NOS and came with some high performance and R3 stuff I bought decades ago.

What is it? Might it be an R3 rear end? Maybe a truck rear end? Please see the pictures.

[JoeHall]

Looks like a model 44, TT, with 4.27 gears, someone may have attached traction bars to, or at least planned to. I can see the 44 on the web by the pumpkin, where it should be. Can also see the factory 1/8" pipe plugs for grease zerts, but pretty sure they stopped installing those in 56, ditto for the drain plug. Being a TT, it has to be 57 or later, but the grease plugs limit it to 1956. It definitely would be a nice setup for anyone in a hurry, and only going 1/8th or 1/4 mile.

[Dwight FitzSimons]

R3 differentials were flanged; yours is tapered.
--Dwight

[StudeRich]

The narrow spring perches give it away, it's a 1/2 Ton Truck, they have larger axles, larger Bearings and a narrower track than a car.
The "Traction Bar" brackets are not Studebaker, must be owner added for aftermarket ones or extra shocks.

That explains ALL of the differences it has from a Car. A 4.27 ratio is very common in Overdrive V8 Champs.

[mbstude]

It's a stock 56-64 1/2 ton truck rear axle. The welded on tabs are the shock mounts.

[M-Webb]

Man, on top of it having a TT rear, that truck of yours has what looks like maybe stainless dual exhaust and a new repro gas tank? That is definitely a cool truck. Or was that the old one you use to have a while back, not the one you have currently?

[studefan]

Thanks everyone for the comments and thanks Matt for the picture and confirmation.

It's for sale if anyone is interested. Free delivery to Washington PA meet if a deal is struck.

[bezhawk]

It's also great that it has a drain plug for the differential. Getting rid of that, and the bearing grease plugs was a mistake in my opinion.
R3 rear ends are flanged axles, and the retaining bolts for the backing plate are beefier at 3/8 instead of 5/16. The outer bearings are a sealed bearing.