hey guys...i might have an answer to the diff fluid, but you prob already have it. i have an arb
locker and needed fluid.. i got a sheet from arb that tells you different conditions and temp ranges and what to use.
for high temp/desert use (temp range -22 to 212 ) it says use shell S 80W-140 or mobil SHC 75W-90..
let me know if it helps or if you want the other temps ranges