Owner's Service Manual and differential/transfer case/transmission fluid change

[KaiHartman]

Am I crazy or does my manual (on service shedule A) not mention changing either one of the differentials' fluid, the transfer case's fluid, or the transmission fluid for at least the first 100k miles?



Service schedule B clearly shows it at 15k intervals for the diffs.



I've read that a lot of people do it at 30k intervals and need to do mine soon, but what about the NV5600 and the transfer case? Lastly, is there a magnet in the bottom of the transmission that should be cleaned out when changing fluid?



TIA!

 

[steved]

Correct, the one schedule has no changes listed... but I feel that's bogus if you want a good return on your investment.

I found the diffs to be fairly easy on *good* fluid such as the Royal Purple I use... the factory stuff was garbage IMHO. I run 85w140 Royal Purple with nothing showing on the magnet between checks. I had a bad experience with 75w90 Mobile 1 in the 11. 50AAM at one fill.

The trans does have a magnet in the bottom (its a flexible fridge-like magnet), between the PTO covers... it is a PITA to get out. They are finicky to fluid... find one that works; and if the OE fluid works, use it. I change about every 20k, but mine is hard on fluid. Redline MTL works best for me...

I use Royal Purple Synchromax in my transfercase... got the idea from another TDR member. It works well, and has worked well for nearly 100k in my truck. I look at the fact it is only a couple quarts, and easy to change. Make sure you remove the fill plug BEFORE you remove the drain to ensure it isn't seized in. I change it about every other trans change (or 40k intervals).

 

[KaiHartman]

THANKS, Steved!



How often do you change the fluid in the differentials?

 

[steved]

I replied to your PM...

 

[StricklandJ]

I replaced differential fluid at the first 15,000 miles with Mobile 1 (75w90) and now have 30,00 miles on truck. What problem did Mobile cause?

 

[steved]

I ran Mobile 75w90 from around 50k to around 75k, at which time I noticed it had changed from a crystal clear oil to a very dark brown and burnt smelling fluid... it also appeared very thin and did not have much "between the fingers" lubricating qualities. I did not tow, and only had highway miles...



I never gave it another chance... switched to RP and have never looked back. I know a lot of guys report good luck with Mobile 1, I wasn't so lucky.