We have a 2014 SR5 with 310K miles on it. I changed the spark plugs and transmission fluid at 120K/240K and soon will change it again. Using Valvoline Synthetic ATF. Differential and transfer case fluid are getting changed every 50K to 60K. Mobil Delvac Synthetic 75w90 in the transfer case, Mobile Synthetic 75w90 LS in the differentials. Engine oil every 10K and recently using Quaker State 0w20 synthetic with Toyota filters.

Recently had the needle bearing in the driver’s side of the front differential replaced with the bushing. That was precautionary due to the mileage on the truck. The oft complained groan is really due to lifts placing a side load on the needle bearing. It got new fluid while the mech was in there.

Also recently replaced inner and outer tie rods. Other than brakes, rotors, shocks, serp belt, and one air valve, that’s been pretty much the work done on this truck.