When to Check Lubricant
It is not necessary to regularly check rear axle ﬂuid
unless you suspect there is a leak or you hear an
unusual noise. A ﬂuid loss could indicate a problem.
Have it inspected and repaired.
How to Check Lubricant
To get an accurate reading, the vehicle should be on a
If the level is below the bottom of the ﬁller plug hole,
you will need to add some lubricant. Add enough
lubricant to raise the level to the bottom of the ﬁller
What to Use
To add lubricant when the level is low, use SAE 75W-90
Synthetic Gear Lubricant (GM Part No. 12378261) or
equivalent meeting GM Speciﬁcation 9986115.
To completely reﬁll after draining, add 4 ounces
(118 ml) of Limited-Slip Differential Lubricant Additive
(GM Part No. 1052358) or equivalent. Then ﬁll to the
bottom of the ﬁller plug hole with the Synthetic Gear