Is It OK to Mix Diff. Fluid?

[JimmyS5600]

Hi, I need to add some diff. fluid to my 99 Mustang GT's
8.8 rear. Is it ok to add Mobil 1 to the "old style" fluid?
Thanks

 

[INDYMAC]

I wouldn't. The chenistry and add pack are totally different. Why not just do a drain and fill? All you have to do is open the drain plug and then refill.

 

[JimmyS5600]

INDYMAC. Thanks for the reply. That is what I intend to do.
Not sure if I should go the syn. route or not

 

[Tempest]

Quote:

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Not sure if I should go the syn. route or not

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Yes. Amsoil or Redline.

 

[another Todd]

Mix away. Won't hurt a thing. But, if your due for a change...well lets just say I believe synthetic is better.

 

[unDummy]

If you're low on fluid, then topping of with any like fluid is perfectly OK and definitely better then being low on fluid.

Since low sometimes means overdue for a change, then by all means maintain that 'end.

 

[Buffman]

I've mixed diff fluids on my ranger cause I was cleaning out the diff cabinet of all the half filled bottles. They were all 80w90, same specs all convential fluid. I don't have any problems. Then again it's my winter truck and anything else I'd just put all the same fluid into it.