Thinking I should change the gear oil in the front and rear differentials, and the ATF in the transfer case. The owner's manual does not give a periodicity for the differential's. It does state 50,000 miles for the transfer case, but I think they are referring to the AWD models. Mine has a 4H/4L style transfer case. I plan to use Mobil 1 75W-90 both front and rear. My rear axle is a limited slip, and I noticed Mobil 1 gear oil has the LSD additive already added. Currently have 75,000 miles on "Thirsty" and hope to keep it for 75,000 more. Any suggestions?