I'm about to change the gear oil in my rear differential, I've done this one time before and did not add a friction modifier. I'm looking on dodgeram.org and it says if I have a trac-lok diff that I needed to add the friction modifier.

Do I need the friction modifier? How do I know?

Suggestions??
My truck is in signature.
-Tim

 

If you have a 5 speed, you do have a Trac Lok Dana 80 rear end.... that is if you have limited slip differential.
There is a metal tag on one of the differential cover bolts that will tell you.
Can also get the info from a dealer by taking your VIN # to a Parts Dept and asking for a "Build Sheet" on your CTD.
Should be free.

Some higher quality gear lube had FM included.... others don't. Tight turns (figure 8's) in a Walmart parking lot will tell if yours is binding or not. If so, needs more FM.

RJ

 

LS needed for track-lok.

 

I just recently re-did my front and back diff & put Royal Purple Max-Gear in it. It's really good stuff & is supposed to really keep the heat down & protect the gears. Price is kind of high compared to the others though. It's not necessary to put friction modifier in this is you use Royal Purple. If you tow a lot I believe you're supposed to use 75W 140.

http://www.royalpurple.com/gear-oil.html