gear oil

[john cris]

Fixin to change out gear oil in front and rear diff on my 03" explorer 4.0 sohc 4x4 Are Amsoil and Royal Purple really worth it? Stuff is like $20 a quart. Vehicle has 150k on it. Don't know when gear oil was last done. I'm thinkin Mercon V in the transfer case and 75/140 synthetic in the diffs. Diffs are quiet without issue now. I'll be towing a boat (3500 lb) more often this summer and just want to do maintenance. Did this on a car I had awhile back and the diff began making noise. What do you think?
John

 

[lincolnshibuya]

i used royal purple for my transfer case and mobil1 for the diffs. there's no point spending on expensive synthetic oils, they're pretty much the same IMO.

don't use mercon v atf in the transfer case.

https://www.youtube.com/watch?v=F7gKtqkuhmU

 

[john cris]

Just a follow up here,
I replaced the gear oil in the transfer case, front and rear diffs. Used Mercon 3 in transfer case, Valvoline 75/140 synthetic in rear diff and Valvoline 80/90 non synthetic in front. Very straight forward stuff. I was hesitant to use Mercon 3 in transfer case but royal purple was not available.
John

 

[drdoom]

You done good