Well I just finished changing my gear oil in the axles and the atf in the transfer case getting ready for the summer towing season and wanted to share my finding with you. It had been 60K since the last time they were serviced. The ATF in the transfer case definitely needed changing as it was starting to get brown/blackish tint to it still not too bad. The axles however were extremely clean with the old oil coming out looking like the new oil going in. I will definitely extend my drain intervals on the axles probably to 100K.

 

What fluid are your running?

 

I run Mobil 1 75W 90 in the axles and Mopar ATF+4 in the Transfer Case.

 

I did my rear diff at 42k miles, and it was grey / black...

I replaced it with mobil 1 75W90 synth

 

I changed the fluid in both diffs at 15k and refilled them with RP 75w-90. I plan to check them at 30k and based on how the fluid looks I'll leave it be for another 15k or I'll change it. The next time I have to change it I'll probably replace it with Amsoil Severe Gear and run even longer between changes. Other than heat there's not much else that regularly effects that oil.