I've searched many forums and can't find a straight answer about the fluid that is supposed to be used in a 2002 transfer case with a centre diff lock. Some say ATF which sounds right while some say 75w90 which I would agree with if it wasn't for the centre diff.

But when I go to http://www.toyota.com/owners/web/pag...Owners-Manuals

under specifications it says this:
TRANSFER
Oil capacity, L (qt., Imp. qt.):
1.2 (1.3, 1.1)
Oil type:
Gear oil API GL–4 or GL–5
Recommended oil viscosity:
SAE 75W–90

and for differential it says this:
DIFFERENTIAL
Oil capacity, L (qt., Imp. qt.):
Two–wheel drive models
2.75 (2.9, 2.4)
Four–wheel drive models
Front
1.15 (1.2, 1.0)
Rear
With center differential lock system
2.75 (2.9, 2.4)
Without center differential lock system
2.45 (2.6, 2.2)
Oil type:
Hypoid gear oil API GL–5
Recommended oil viscosity:
Front
SAE 75W–90
Rear
Above –18
C (0
F)
SAE 90
Below –18
C (0
F)
SAE 80W or 80W–90

seems to me that the center diff lock has nothing to do with the diff. I find it hard to believe but does Toyota still have this information wrong in the manual 12 years later?

 

i was surprised to find that it actually was gear oil in there. it drained out redish brown but definitely smelled like gear oil. i refilled it with some synthetic stuff and it shifts in and out of 4wd easily now. before this i had to go back and forth couple of times to get it in and out of 4wd and to get the centre diff lock to work.

 

Toyota simply uses gear lune in the transfer case. The only requirement, as you stats in your first post, is that it meet GL-4 or GL-5 rating.

A possible reason for reddish fluid in the transfer case is possibly a leaking transmission output seal. I've seen it a lot on dodges and Chevys, and a few 4Runners and Tacomas, where the output seal will begin to fail, and fill the small area between the trans and transfer case. Once this space fills, it will then begin pushing fluid into the transfer case, overfilling it and making it difficult to shift. This overfilling scenario only happens with a automatic, which I'm assuming you 4Runner is. As long as it wasn't severely overfilled, I wouldn't worry. I'm just putting the info out there.

 

I change the oil in my front diff, transfer case and rear diff every 50,000 miles. I've done this since buying the truck new and now have 295,000+ miles.

Mobil1 75/90 gear oil. No issues.



Andreas