1998xjspt

what kind of oil should be used on stock d30/c8.25 axles? i searched a bit and all i see is mixed answers and answers specifically for people who are running different gears and lockers and whatnot. so what should be used for stock axles?

JeepMoreDoor

My 2000 cherokee manual says 75w-90, so you can use that or 80w-90. The d30 just runs gear oil, the 8.25 usually requires a friction modifier added to the oil if it has limited slip. Supposedly, some oils you don't need the modifier...

salad

75w90 or 80w90 is fine front and rear for normal use. If you're beating on the rear axle (offroad or towing) then fill with 75w140. If you have a limited slip in the back you'll need to make sure the friction modifier is present. Most 75w140s I've seen on the shelf at the store seem to have this already added though.

If you like fuel economy, apparently using a synthetic gear oil makes a big difference. However if you sink your axles it's a better idea to just run conventional and change the fluid regularly. The axles are not water tight, and you definitely don't want to let water sit in there.