I apologize if this question has been beat to death, I did a search on the forum for my answer and found conflicting answers, so I had to start this thread. I bought the Mopar differential lubricant from the dealer and took it to my mechanic and he forgot that I had bought it and set it on his shelf and overlooked it and ordered Valvoline syn power full synthetic 75/90 and told me it was a better lubricant and to take the 2 quarts of Mopar stuff back to get my money back. The car is still up on the rack and this morning I asked him to drain it out and put in the Mopar stuff I had brought to him. I haven't gotten a reply yet. He has a shop with several Vintage restored Fords, Chevy's and Dodges and a TR-4 he is working on. Will this Valvoline lubricant work properly or turn into molasses like another post I read. If it will work, then I'll call him and tell him nevermind the fluid change. What do yall think? Thanks in advance. Peace.

 

I think the guy is right, Synthetic 75/90 is what I put in mine, after talking with several guys on here.

 

But I use Mobile 1 stuff....

 

Thanks PG, he said he would drain it and put in the correct fluid. He also said that it was clear and looked as if it had been changed, but I had no way of knowing. Someone must have been trying to quieten the wheel bearing which I was told by the dealer needed replacing, so I'll hunt up a couple of bearings while its up in the air for him to change out. peace

 

I put Royal Purple in mine.

 

Motul in mine.

Les

 

Amsoil 75W-90 Long Life Synthetic Gear Lube in mine.

 

My point was that synthetic 75-90 seems to be the verdict, and that appears to be supported by the posts here.

 

I believe this is the recommended lube for the Crossfire rear end . . . This is also what WaveTrac recommends to use if you have a WaveTrac LSD installed.



However I personally don't think you can go wrong with the correct weight name brand full synthetic oil.

 

Motul gear comp 75/140 in my car now, with the WaveTrac. Used the MB hypoid oil in the stock diff.

 

Per owners manual (2004) and (2008) -
Only use synthetic SAE 75W-85 axle lubricant that meets MB 231.1.
Reduced axle durability may result if an unapproved product is used.