Hey guys,

Just purchased a 2003 Ram 1500 and have been reading up on the forum. One thing I want to do ASAP is check the differential(it does have Anti-Spin)/change the gear oil as I don't know the history and the truck has 57K miles on it. I see the manual specs 75W-140 gear oil but the only thing the auto stores carry in that weight is synthetic at like $13 a quart. I did find 85W-140 in conventional though.

Is Synthetic required? Recommended? I don't recall what the manual said.

If not, will the 85W-140 work OK?

If not, anybody know where I can find 75W-140 conventional oil.

Thanks,

Kevin

 

Use the 75w-140 you can Get it at walmart cheaper and yes its synthetic.

 

I am pretty sure Synthetic is required along with some type of anti slip additive.

 

Yeah you definitely don't want to forget the lsd additive. I've heard if you use royal purple (quite spendy) the lsd additive is already included.

 

Well in Canada Mopar 75w140 is $31.45 per quart + 14% tax. Ouch ****** ripoff.Dealer parts guy saidyou can run 75w 90 in rear end if not towing. I did not verify that in the manuel. Summit racing carries 75w140. TheRedline synthetic brand is approx 8.95/quart.Don't even consider a petroleum base oil back there. Synthetic all the way! Also if 4x4 don't forget the front axle and transfer case.
Dan