How do I change the gear oil on a 93 Jeep Grand Cherokee?

I'd like to sell a 1993 Jeep Grand Cherokee Limited but my ex-roommate mechanic didn't put gear oil back in the casing on the front axle (front differential?). I see what looks like a square hole which I assume is the plug. How might I go about adding more gear oil on my own?





I have a very limited understanding of auto mechanics and would appreciate any help.How do I change the gear oil on a 93 Jeep Grand Cherokee?
It is the front differential. Remove that drain plug, buy about 2 quarts if 75w-90 gear oil and ask the parts store for a tube to attach the the bottle to fill the differential. It is full when you see fluid start coming back out. Good Luck!How do I change the gear oil on a 93 Jeep Grand Cherokee?
Open that hole and drain any fluid if there is any left, then go out and buy a couple of bottles and fill it, once the fluid starts coming back out of that hole, stop and put the Cap back on... thats it, i have done this to many cars before, very easy.