FWD = front wheel drive. A Cherokee is either rear wheel drive (RWD) or four wheel drive (4WD, 4x4), never FWD alone. All standard, road driven cars have differentials whether they be FWD, RWD, or AWD/4WD. Front wheel drive cars just tend to have the differential incorporated into the transmission housing and sharing the same fluid. Of course use the correct fluid for your transmission type - ATF (automatic transmission fluid) for an automatic, or regular gear oil of the appropriate weight for a manual transmission. Any normal 30w (eg 10w30) will work in a pinch for a normal manual trans. For the automatics it's generally preferred to use honda genuine ATF since it has additional additives. I've used Valvoline ATF in mine and it worked fine for the 30 or so thousand miles it was in (216k miles on the trans). The honda genuine fluid just gets a bit pricey at $5+/quart.

Stand alone differentials (eg the rear diff in a RWD vehicle) tend to use a heavier weight gear oil such as 75w90, and some people like to use even thicker. Regular gear oil can smell pretty bad even brand new, depending on the brand you buy, so smell's not a real good indicator of anything.