Originally Posted by rftroy
Originally Posted by AndyF
Talk to Cass at Doctor Diff. I'm pretty sure the helical is the way to go these days. They are much smoother than a locker and much more reliable than the old clutch pack design.


Yes. Call Cass.
Avoid the Eaton Detroit Truetrac. They have quality issues with the Chrysler 8-3/4 version. I got one and had to send it back. It had a tremendous amount of side play on one of the output worm gears that engage the axle splines. Many reports on Mopar sites about this problem. The play causes the axle splined end to move side to side, in two dimensions, and therefore the wheel to wobble. People have also reported clunking noises.

Robert


These are good info. Cass build my A-body 8 3/4 and I had the issue with the play mentioned above. Cass then built me a 489 case 3rd member with the helical Eaton. The only thing I can add is to make sure you use the gear oil without the friction modifier in it. I used the dinosaur oil initially, but now I'm going to use the Redline synthetic without the friction modifier in it. The issue is how hard the wheels lock together which changes with the various gear oils.

1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)