downwardspiral

I just picked up some richmond 4.11's with a ford racing trac-lok (basically a detroit locker) I was just wondering, would it make a difference if I used Royal Purple? I hear its good stuff, but I can get plain synthetic for cheaper.

Chopper

I'm getting ready to install a Detroit Tru-Trac and am going to use Redline lube but for installing gears I would use something cheaper untill you get the five hundred mile break-in finished then put in the lube of your choice.BTW,the Ford Racing Trac Lock is a clutch type differential and requires a friction modifier.

p0rsche23

nice info

downwardspiral

What is a friction modifier?

kartracer55

If its like What GMs use in thier posi's its just an addative you pour in with the gear oil, and its expensive as hell (relativly). Also, Lucas usually makes really good stuff, you cant go wrong with them, so if you can get it cheaper than go for it.

Jim

Deannostang

Royal Purple, Redline, Amsoil are all good products. Always safe to add friction modifier as required by Ford to any new rear end fluid. Some synthetics say you don't need to but I would rather error on the side of caution instead of blowing up my new rear end. Anywhere that sells Ford Racing gears will also have the friction modifier. Your local Ford dealer is also a good source. Don't forget at least the basic install kit for your new gears. Can get the kit with new bearings too if you have many miles on your ride. Good luck.

downwardspiral

Oh, thanks alot. I'll ask about it when I pick up the differential on Friday.