I just changed my rear diff fluid with Valvoline 85-140 synthetic blend oil.
A guy from work says he uses this in his T/A that's why I decided to try it.
I havn't added any posi lube yet,just wondering if anyone else has used this oil and if you used the posi additive?

 

If you have a posi, you'll need the additive.

That's the wrong lube.

You'll gain about 2 miles per gallon, and probably some parts life too, if you take that candle wax out of there, and put the right stuff in it instead. Which is 80W-90 or 75W-90. These rears (unlike some other models) don't benefit from the thicker lube, and it can actually harm it, because it doesn't flow around in there like it's supposed to.

 

Yeah that's exactly what I was thinking when I was pouring it in was how thick it was, like sludge.
I think I'll just change it again with 80-90.