Help with Differential problem on 1957 Transtar (3E7) - twin traction

[tim mccracken]

Thanks jpepper. Good info and advice. On the sites you listed, I find rings/pinion kits aplenty, but none of the internal parts look quite like what I see in the Studebaker parts books for the Twin Traction diff. I will paste an image here. I haven't seen anything with a cross pin that looks like those in the image below. Am I missing something?

I'd appreciate any any input on further options. An un-rebuilt, used donor could be inexpensive but potentially risky, and if replacement internal gears/shafts aren't available a potential future problem (please tell me i am wrong on the replacement parts). I've seen some aftermarket units (Auburn/etc), but don't know if there would be complications or quality issues.

Any and all input is appreciated!

[RadioRoy]

I would not be afraid of a used one, especially from as good a mechanic as Pop's Chariot. In my experience, differentials are pretty sturdy as long as they have not been run dry.

[tim mccracken]

Thanks Roy - Pop's Chariot and I are PM'ing.

[jpepper]

The Studebaker TT unit is a Dana Power Lok two piece unit. They also made a traction lok one piece unit. They are completely different. Nels is correct about the center thrust pin. It is a two piece assembly held together with a spring pin. The spring pin is the Achilles heal and it can fail. Also with enough torque, the separating forces can be greater than the yield point of the bolts holding the two halves together. When that occurs, there no longer is any clamp load and the two halves move/slip. In a short time you will shear all eight bolts. Over the years I have sheared the bolts in both a Dana 44 and a Dana 60. Dana made a Power Lok to fit the 55 - 64 Chevrolet rear end. The same failure occurred there especially in 409 cars. Try this for an internal clutch kit. http://www.drivetrainamerica.com/222...4aAqWXEALw_wcB
or

https://www.summitracing.com/parts/yga-16151

I am assuming the pinion shafts, differential pinions, and side gears are okay.

[acolds]

shows difference between units