I want to install a torque spltting differential in my now open diff 1970 8-3/4 489 axle with 3.23 gears. Axle works good with no noises but has lots of miles on it so I would like to do a rebuild at the same time. Then, when the car goes to restoration in the near future the axle work will already be done. Car is a Chrysler 300 Hurst.

Question 1:
What differential carrier should I use? The Truetrac doesn't get good reviews for the 8-3/4 axle and the cone style doesn't either. Is there a good clutch style diff avilable for the 489? Powertrax Lock-Right might be an option but is a locker so I'm not sure that would be a good choice.

Question 2:
What parts, other than wheel bearings and their oil seals, do I need to do a rebuild assuming the gear set can be re-used? A complete list and advice for good parts would be great!

Thanks

I would purchase a good tight 742 case sure grip ready to drop in pig in the ratio you desire. all that is left is a ring gear gasket, axle bearings, (2) collars that lock the bearing in place (2) inner seals that you drive in the housing and the (2) flat flange seals, one has the threaded adjuster and the other is just flat with no adjuster, and a pair of white foam gaskets and a pair of the steel shim gaskets, the lube and a vial of SG lube. Plus your brake stuff EDIT the pig would need the (2) "buttons" and the roll pin that holds em together & likely it'll have em when you purchase it. these are the flat pieces installed on each side of the SG assy that the axle splined ends butt against them where they contact the SG so the end play can be set

I run a clutch type sure grip in my 489 E body rear. It has quite a few road miles plus road track time. No issues. I think the clutch type is the best bet at this point... especially as there are quality issues with the worm gear type and the cone type is weak.

I believe Dr Diff is offering clutch type now.

I'm suspecting a restored 300 is probably not going to see much track action. If it will be for street use, I see no reason the cone type unit wouldn't work. Of course, its your ride, build it over kill if you want. Gene

Thanks guys! I'll lock into this and might come back with more questions. If I can get a clutch type diff I might go for that. Sure the car is, and will be, a cruiser but wifey likes to hammer on it at the track a couple of days in the summer and she isn't really too kind to it:)

For street use I don't think you can beat the TruTrac. The best clutch type is the Powr Lock. There might be a new one on the market. The Auburn Gear cone type would probably work as well as the PowrLok but as it costs the same and isn't rebuildable there's no reason to buy it.

If you have slippery roads from time to time, a clutch or cone type differential might not be the best choice. When in the snow both wheels spin and if you're on a slope there's a tendency to slip sideways.

DoctorDiff has both the Trutrac and PowrLock listed. It'd be worthwhile to contact him and get his opinion.

R.

I'm a fan of the old (old!) Reliable Detroit Locker.

In a heavy long wheelbase vehicle, they work well.

Yes they have some quirks, clunk and sudden lock or unlock, but you get used to them and its no big deal.

Fwiw, I've logged over 200k miles with em and never had a problem.