I'm getting mixed responses. My installer put royal purple with the additive in when he changed out my gears and posi unit. I need to change the breakin oil out should I put dino+additive or stick with the RP with additive. I some telling me that it's fine and some saying dino+fords additive is the best route.
I posted this is the gear section but didn't get any responses. I'm swapping the oil this weekend and I want to put the right stuff in.
Thanks,
Lar

 

I used Mobil 1 with the GM additive on my auburn and it's just fine.

 

When I got my Eaton, it says on the instructions to use GM minerals...including the LSD friction modifier. It even gives the part numbers.
Just pick it up at your local stealership.

 

Just wanted to clairify:When i installed my Eaton i did what Randy ring and pinion said to do.I did a synthetic "BLENDED" 90wt,that means part dino and part syn.Also the ford additive is cheaper than the GM and works better so he says.