Interesting correspondence from Cass at Dr Diff

[7E-Bodies]

Going through my 8-3/4 for my JS23U0B restoration has been a fairly pleasant learning experience. The previous owner truthfully told me it's original 3.23 was long gone. Replaced by a 3.91 SG in a 741 that I wasn't keen on running with. After tons of questions and reading, I finally reached out to Cass and ordered a ready to go 3.23 center chunk complete. The only place I cheated was I wanted Sure Grip. In a few days, my 95# wife mistakenly tried to lift a porch dropped package that she thought was something else. Let's just say it was still there when I got home  When I unboxed it, it just seemed to look different than the 3.91 I'd removed. Lots. Upon emailing Cass, he sent me the following links after saying:
"This is a 6 helical gear (torque sensitive/torsen) differential.  It does not use clutch plates or cones like a traditional limited slip differential.  See below:"

https://www.youtube.com/watch?v=lZmsY2YvVsc

https://www.youtube.com/watch?v=JEiSTzK-A2A

I'm now pretty stoked about it all and looking forward to spinning this thing! The videos are amazing. The attached pictures are of the 3.91 I pulled (no yellow on ring gear) and the new 3.23 (yellow on ring gear from Cass setting it all up).

[Chryco Psycho]

Nice upgrade 

[dodj]

 
I have an Eaton trutrac which is built on the same principles/torsen.
Put it in 2 or 3 years ago. Been very happy with it. Insofar as since installation I haven't had to do anything to it.
Without the cones etc they don't wear out like a traditional setup..

[7212Mopar]

I am running the same setup from Dr Diff, 3.23 ratio as well for highway driving. No problems for about 4000 miles now. No funny noises going straight, turning and at different speed. Got up to 110 mph once. Lay down two stripes when you want to. I am very happy with it. Just use standard gear oil without friction modifiers as there are no disc packs. Thus also no adjustment needed, just change oil.

[Filthy Filbert]

A note on how those things work.   

They need torque to 'activate' so light easy driving around a corner, it acts like an open diff.  No ratcheting no grinding no tire chirping. Just nice and smooth turning.

Mash the gas and it locks up like a spool with no slip. 

With the tires off the ground, they will rotate opposite of each other like an open. 
One tire on wet grass and one on pavement, it'll act like an open.  In those situations, you may need to ride the brake to get enough torque to activate the diff and not get stuck. 

[Brads70]

I've got one in my Dana S60 and love it. Works great very happy with it.  I also have another  Dana in the Javelin and it has it too.

[7E-Bodies]

Awesome feedback, all! I now am super stoked about this phase of the restoration. Can a few weigh in on how you clean out the axle case? Right now I'm tempted to spray diesel in each end (outside of course), scrub out each side with a toilet brush rigged to a long plastic rod and repeat, let it puddle in the pumpkin, wipe it out with a rag, let air dry in the sun (paint and clear coat need to cure anyway). Scared to use any kind of solvent with gear lube soon to go in. Looking for suggestions.

[headejm]

 

[7212Mopar]

I did mine with the outside using wire wheels on a hand drill. After that some 100 grid sand paper to get the tough to get spots. Then I removed the axle seals, brush the inside clean like what you are thinking except I used engine decreaser. I also wire wheel the inside of the center housing and the mounting flange, studs etc to remove as much of the surface rust I can. There will be spots you won't be able to get to. After that wash with detergent and hose off and blow dry. I applied some rust magic to the inside as well to keep it from rusting since I did not reassemble till much later. The outside was just prime and paint. I should have send it out to get powder coated.