I believe I have what looks to be a leaking outer axle seal, but I have no time to repair this untill next week..

I plan to just top up the diff if it gets low..

What kind of gear oil do I need?

And what is the procedure for checking the Diff fluid level? Should it just be at the top of the filler hole?

Thank you.

 

80-90 gear lube (with friction additive if you have limited slip diff)

Fill to the BOTTOM of the fill hole. Otherwise, it runs out.

 

which axle, front or rear?
and which truck, 1500 or 2500?

if front, and if 1500, there is no "outer" seal. instead the seals are inconveniently located deep in the tubes. drivers side at the diff, passenger side at the cad.

just keep it full and you can let it leak for a long time.