99 limited 4x4 full service

[SaltyNaulty]

Just picked up a 99 limited 4x4, I run a car wash/lube shop here in town so on Monday it will be getting an oil change, front/rear/tcase fluid change, coolant change, power steering fluid change, etc.

My question is what fluid to use in the gearboxes and what I should do about the transmission being at 137k miles.

Thanks!