Which transfer case fluid does everyone use?

Just wondering, do I have to use the new blue x-case fluid from Chevy, or can I use Mobil1 or Royal Purple. I have an '02 Z71 with autotrac.
Also, which diff fluids does everyone use, I'm about to change to Royal Purple 75-90
Thanks,
Jeb

i think it;s just tranny fluid

Red Line MTL....... I've had it in for the last 10,000 miles and everythings' fine. Heard you shouldn't use anything except GM blue......... I called Red Line and they said it was a compatible alternative.

Don't use anything other then autotrac 2 blue stuff from the stealership. Some people have gotten that horrible clunking noises from not using the blue stuff.....don't use tranny fluid, this was for the older trucks... some people may use mobil and not get any noise but others will go bezerk.....I had changed all my fluids (tranny, engine, both diffs, transfer case) to royal purple fluid....After 10,000 kilometres and all I heard was clunk, clunk.........drove me nuts and then gm came out with the tsb that said to use the new transfer case fluid.....I changed over and no more clunking......other's will chime in and tell you the same thing........

only use auto-track if you have the auto 4x4 option otherwise use dextronIII. trucks with auto 4x4 have clutch packs in the transfercase and need whatever they put in the blue stuff

what year did they saya to use the blue stuff? mine has D-III in it? 2000 z-71 4x4 5.3

All 4 by 4 trucks, should use the auto trac fluid......Even some of the older vehicles, 1990...1995 and such.....had before the tranny fluid (red color) and now everyone is to use the new blue stuff (auto trac) You can check the service bulletins from GM......In other words, use the blue stuff, change it every 50,000 kilometres and you should be all right.....

I changed my transfer case fluid and put in the Auto-trac II from the dealer(2 quarts at about $6.50 per, not too bad for the stealership). Turned out my truck already had it since it's a 2002, but it was due for a change anyway.

I also bit the bullet and changed my front diff to 75W90 Royal Purple ($8.99 per quart). Someone told me the front diff took 3 quarts, but I only needed 2. While I had the plug out I took pictures of the amount of shavings and sludge on the magnetic drain plug. I know some amount of gear wear is normal, but this seems excessive.
Before:
http://files.automotiveforums.com/gallery/watermark.php?file=/500/110425diffboltbefore-med.JPG
After:
http://files.automotiveforums.com/gallery/watermark.php?file=/500/110425diffboltafter-med.JPG

Jeb

I'm starting to worry,...I can't find a reliable source anywhere that says my truck is supposed to take 2 or 3 quarts of front diff fluid. When I finished the second quart, fluid came pouring back out and I stuck my finger in and down and it felt full. Can anyone confirm that my front diff doesn't take 3 quarts?
thanks,
Jeb

I'm starting to worry,...I can't find a reliable source anywhere that says my truck is supposed to take 2 or 3 quarts of front diff fluid. When I finished the second quart, fluid came pouring back out and I stuck my finger in and down and it felt full. Can anyone confirm that my front diff doesn't take 3 quarts?
thanks,
Jeb

I looked all through my Haynes manual and all it says is to check the level as you have done. Doesn't list an actual capacity. I think you're O.K. I would just drive it a while then let it sit a while on a good level surface and check it again. The fluid level should be below the fill plug opening 1-5/8 on the 1500 series models and no more than 3/8 inch lower than the hole on the 2500 series model according to the Haynes manual.

I just found this link. It lists 3 quarts cap. for the front.

http://gmdiy.info/diyfluids_diffchange.html

Yeah, my Haynes manual says the same thing. I saw that site too, but I think it's wrong. It just doesn't make sense.

Bulletin No.: 99-04-21-006

Date: September, 1999

INFORMATION

Subject:
Improved Automatic Transfer Case Fluid

Models:
1999-2000 Cadillac Escalade
1998-2000 Chevrolet and GMC K/T 4-Wheel Drive Pickups and Utility Models
1999-2000 Chevrolet and GMC L Van Models
1999-2000 Oldsmobile Bravada
with Active Transfer Case (RPOs NP4, NP8)

Effective with vehicle production in late June of 1999, all active transfer cases on the above listed vehicles have been filled with Autotrak(R) II fluid, P/N 12378508 (P/N 10953626 in Canada). This fluid is a light blue color rather than the red color of the previous fluids and is the next generation Automatic Transfer Case Fluid. The fluid also contains a better friction modifier. On the models listed above, the active transfer cases should only be serviced using P/N 12378508 (P/N 10953626 in Canada), even if the original fluid was the red Autotrak(R) fluid. The previous fluid and the new fluid can be mixed or topped off if necessary. The new Autotrak(R) II fluid will be the only available fluid once the supply of the old red Autotrak(R) fluid is exhausted on units older than stated above.