Doesn't matter which axle you have, the requirements are the same: 75W-90 API GL5 for the axles, Trac Lok additive if you have a limited slip, and 75W-140 synthetic if you're doing heavy towing. I think the tow package versions come with the synthetic in. I put synthetic in the rear end of my 95 which was kind of noisy. It helped very little, but certainly did no harm.
Transfer case takes Mopar ATF, Dexron III or Mercon.
As far as I know, if you have ABS, you get the Dana 35, or what is described in the 99FSM as the 194RBI. If you have conventional brakes, you get a Chrysler 8 1/4. Either can come with Trac-Lok optional. On the cast reinforcing webs of the case of a D35 you should see "D35C" and the Dana logo. There are no such webs on the 8 1/4. If you take off a hubcap or a wheel, Dana Axle ends have a depression that looks sort of like a figure 8 or an hourglass. Chrysler ends are like a simple rectangle with rounded ends.
Capacites from the 99 owner's manual:
Transfer case Selec-Trac = 2.85 pints, 1.3 liters
""Command Trac = 2.2 pints, 1 liter.
Front axle = 3.0 pints, 1.5 liters
Rear Dana = 3.4 pints, 1.6 liters
Rear Chrysler = 4.4 pints, 2.0 liters