Transfer Case Fluid

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by deployedtater, Nov 2, 2013.

  1. deployedtater

    deployedtater New Member

    Has any one ever changed their transfer case fluid and found it to have the wrong fluid? I have a 2005 GMC Sierra 1500 with 61k and bought in new. Started having a loud grinding/popping noise anytime I put it in 4hi or 4low and made a turn. Took it to the dealer and they found that it had a yellow fluid (I think it was gear oil) instead of AUTO-TRAK II. I did change all the fluids at 50k except that one cause I didn't want to pay $30 just for fluid and had read in many posts that if not used heavily it can make it to 75k or more. Any ideas? I was thinking maybe it was a preservative or at the time that is was the color of AUTO-TRAK II.
  2. j cat

    j cat Epic Member 5+ Years 1000 Posts

    the fluid is to be blue. some have used dexron III fluid but GM now requires the use of autotracII fluid because of the components used.

    my guess is they used the manual transmission gear oil . this fluid is like a 30wt oil but has additives to prevent bushings from wearing out. also improves manual shift effort ..

    I would replace this fluid with the transfer case being warm after the vehicle has been used for a good hour or so... let the fluid drain out for an hour or so. then add the 2 qts/maybe a few ounces more with a qt hand pump tool. do not over tighten these plugs the case will crack.10 ft lbs is all that is required.

    check fluid after a few weeks . if it starts to look off color replace again. I would replace again any way !
  3. grampy

    grampy Rockstar 100 Posts

    Just looked at the book for my '07, 2500. Recommendation is Dexron V1, same fluid as auto. trans. I would follow j cat's advise, change it twice. Who knows what's in there ! Some one at a lube place may have been "old school" and put something like 90wt. in it. Probably a good idea to do the change ASAP, it's going to get chilly soon ! KEN
  4. deployedtater

    deployedtater New Member

    Thanks for the replies. This is one reason if I can do the work my self I will. I haven't let anyone change any of the fluids except myself so I know it was never changed. When I had the chance to get an extended warranty I jumped on it, problem is now that we found the wrong fluid in there they may not fix it if there is an issue and its been in there for 60k miles. Dealer said they flushed it but I will check it after a few days of driving. The noises have stopped now it just moans which I don't remember it did before or not.
  5. j cat

    j cat Epic Member 5+ Years 1000 Posts

    this may cause warranty issues with the wrong fluids...

    check the fluid color after a few hundred..

    on the transfercase fluid//// the fluid must be changed when it turns gray blue. this is the time to do it..the use of the vehicle may not effect this at all...

    even if you never use 4wd this fluid does work...

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