What differential lube oils should i use?

Can someone tell me which oil/lube to use on a 99 XJ with a 8.25 rear end and standard Dana 30 up front? Do I need any additives in both axles?

my Jeep has 120,000 miles on it if that matters.

Whether or not you need additives depends on 1) if you have a factory limited slip in the rear and 2) the gear oil you choose already has the limited slip additive in it, which many do. You shouldn't need any additives in the front if your jeep is stock.

I have 150,000 miles on my jeep and I use 85W-140 synthetic blend in the rear and usually 75W-90 in the front. Do a search for "gear oil" and you will find this discussion.

I use the Lucas gear lube and have had no problems at all. My daily driver has 289,000 miles on it and I have been runn ing Lucas in it for the past 150K. My rail rig had 150K on it before I blew the motor, but the axles never gave me any problems and I used Lucas and Royal Purple in them since I bought it. Just my $.02