Posi diff. oil

[Micah]

I'm planning on changing the oil in the differential tomorrow. I know it's supposed to be filled to just below the check thing but oes anybody know how much it takes? Am I gonna need more than 1 qt? Also if I use Mobil 1 do I need to add the posi additive?

 

[Two Lane]

Micah,

When I change mine, I use Mobil 1 gear lube with 2 of the little bottles of GM posi-additive. Most people don't change the differential fluid. You're wise to do so.

HTH

 

[MeanBuicks]

Originally posted by Two Lane
Most people don't change the differential fluid.

I'm trying to change mine on regular intervals...every 100,000 miles. Come to think of it, I'm 7,000 miles overdue for it's second change. Yikes!

 

[Micah]

yeah, im pretty sure its been about 122k since the cover has been off on the gears. I'll have to get a sticker on the window to remind myself to change it at 222k. thanks guys

 

[zam70]

just did mine. 2 qts, one tube of posi additive.

 

[tom h]

Mobil is vague whether or not a limited slip additive is req'd with Mobil1.

Some types of Castrol gear oils, for exmpl, say they *are* suitable for use "as is" on limited slip diffs.