Hit 5K miles on my 09 Tundra this week so I decided to change the diff fluids. VERY glad I did. SOmething I never did on my 07 Tundra.
Front diff was a real PAIN!!!!!! It takes a 10mm allen key to remove plugs. The fluid was black and the smell was something I have never smelled before. Enough to make you gag. Anyone know why that is? Changed it to Royal Purple 75w-90. Hardest part is getting new fluid in. You will definitely need a flexible hose to get it done and PATIENCE. I had at least half a quart in my hair by the time it was done.
Rear diff was MUCH easier. Only prob I had was lack of proper socket. I borrowed neighbors 15/16". Strange to me cuz everything else is metric. I think a 24mm may have been better but thats what I had and it worked. When i pulled fill plug there was the "sucking" sound that I had read about in the DIY post. Is this an issue?????? Used the Royal Purple 75w-90 there as well. The fluid in the rear did not smell nearly as bad as the front.
Anyway, just my observations. Definitely recommend changing out the fluid early for break in purposes based on what I saw. The Royal Purple was deffinitely not cheap. Im sure Mobile 1 and other products would have been just as good and a little cheaper. I just wanted to try something new.