If it where me and it has been many times, for the Tremec T4 and T5 transmissions (non-world class like those in your Jeep), you'll need a gearbox oil with anti-oxidation additives like Pennzoil Synchromesh due to the brass synro rings used. The transfer case is good with whatever weight is appropreiate gear oil for your climate (80-90, 75-80 etc.) as long as it meets API-GL5 ratings. I normally mix 10-15% of Lucas oil stabalizer into both before adding.