Bought my truck new in late 2006 and never changed the Gear/Transfer Case oil. With 77k miles on it, I know I'm well past the scheduled changed. What's the best oil out there and do you recommend a bigger cover? Truck runs fine and I haven't felt any problems/noises yet. Thanks.

 

Put 75w-90 in mine a while back and no problems yet. Always questioned the diff fliuid changes and realized it was a waste of time. I towed HEAVY and changed the fluids at the recommended intervals and it was not needed. Just check your fluids and make your own decision.

 

Transfer case is ATF+4. Gear oil is 75w-90. Use a synthetic of choice making sure it meets the GL-5 spec.

Amsoil is my preferred fill.

 

I changed mine at 34000 and it was BLACK. I was really surprised. I dont use 4 wheel al that often...

 

When I first changed my diff fluid at 75k after heavy towing I found that the owners manual was WAY WRONG!! My fluid still looked like honey. Did that 2 more times and realized it was a waste of money. Put the 75-90 in it and have never looked back.....closing in on 300k now!!!! Put the same fluid in t-case as well.

 

ATF+4 only in transfer case