Rear Axle: What diff do l have?

[Bruv]

I got a diff with a 45 tag & a 4.09 tag. It's got no 'C' or 'B' with the 45. Think it came from a 61 Champ. Am guessing it is a TT diff. Can l replace my standard 3.54 diff with it?

[63r2]

I would say it's a Dana 44. The 45b or c tag designates the clutch type used in the TT diff.
If you take the filler nut off the back and you can't put your finger inside the diff housing then it should be a TT.
You should be able to change the Crown wheel and pinion to suit what ratio you want.
You could change the whole lot over but the Champ diff is wider and axles thicker than the standard car so the car hub/brakes etc might not fit.
The Champ diff may also have a larger wheel nut diameter so your rims may not fit.
pb

[Warren Webb]

Champs do have a wider bolt pattern- 5 on 5" whereas the regular Stude cars are 5 on 4.5" The axle assembly is wider too.

[StudeRich]

If your "Std. Diff." is from a Stude Truck and a complete Unit with the outer Housing, yes there is no reason why you can't change from a Twin Traction to a Std. Open Diff. as long as you are working with 2 Cars or 2 Trucks, as Warren said they can not interchange.

Please Note that there were no Studebaker 3.53 Ratio Axles.
If you want to just change the Ring and Pinion to a different Ratio, that can be done but with limits to the Carrier sizes to handle the different Ring Gears.