Welcome to the Z. It's a d30 front axle and either a d35 or d44a rear axle. The Grand Cherokee's rear Dana44 axle is a little unique in that it has an aluminum center section and is prone to go through bearings.
Thanks for the info guys, what about lift kits for this Cherokee ? I'm ok just running 33's . I don't want to spend 2k on a long arm kit because I'm going to build a xj for that but I want a nice lift for the $$
I went for the rough country 4" x-flex kit. Upgraded shocks. And quick disconnects on the front. Everything worked awesome on my 98 ZJ but the rear track bar bracket. Just a little mod and it works fine until i replace it with an adjustable one. All out the door for $1100. I did everything thru kevinsoffroad.com. i live in Phoenix so i had them do all the work as well. They are GC specialists and a quick call to them will handle all the details and get you set up right. Talk to either Kevin or Bryant.