Please, rephrase the question. You say you have a 1989 Jeep Grand Cherokee, but the Grand Cherokee did not come out till late 92, but was considered a 93 model. If what you really have is a 1989 Cherokee, we need to know the motor size. The rest we can look up and give you the best answer possible.
It is in the center of the cover on the rear.
Usually that's in reference to the differential (the centerpiece on a axle) as it is round like a pumpkin.
The differential covers are sealed with RTV silicone. There is no gasket.
There are several things that can cause your 1993 Jeep Grand Cherokee driver information Center not to work. The most common cause is a blown fuse.
At 18000 miles if towing
In the differential
The front differential uses 80W90 gear oil.
YesYes
The bearings are damaged.
It could be differential bearings.
It is in the center of the cover on the rear.
The bearing are sealed and can not be repacked.
Probably a breather pipe for the front differential.
You can find the schematics for a front differential on a Jeep Grand Cherokee 1994 at various auto part stores. You can also check in the owner's manual.
No, use ATF only.
This is often from a dead battery.
Usually that's in reference to the differential (the centerpiece on a axle) as it is round like a pumpkin.