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Thread: Transfer Case Fluid

  1. #1

    Default Transfer Case Fluid

    I have a 2003 2500HD with a Diesel and an Allison Transmission. The dealership told me it has a MP263 Transfer Case. I was also told to use Decron III in the transfer case, When I drained the old fluid, it was not red. It looked like motor oil.

    Any suggestions?

  2. #2
    Join Date
    Apr 2001
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    CA
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    13,573

    Arrow

    The original fill, and service fluid, should be ATF. The same stuff recommended for the Allison tranny. Motor oil, while it may have sufficient lubrication properties, is too heavy. If the TC seems to be operating normally, I suggest a fill with ATF, and a short change interval (maybe a few thousand miles). Don't look back. Odds are, no harm done.

    On the other hand, if the lube was very thin (like ATF or thinner), you may have issues with the TC (contaminated fluid or an overheat issue). Was the fluid level normal? A series of events (however unlikely), could allow fluid to migrate from a leaking rear tranny seal into the front TC seal. I've seen it happen, but it's a million to one chance.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  3. #3

    Default Transfer Case Fluid Change

    Have a 263 Transfer Case. Was told to use Dexron III ATF Fluid. When I drained the old fluid out (original) it looked like oil. Is the Dexron III the corect fluid.

    2003, 2500HD, Diesel, Allison Transmission

  4. #4
    Join Date
    Dec 2010
    Location
    Felton, DE
    Posts
    35

    Default

    I just picked up an 04, and changed all my fluids. I put in Dextron VI on the advice of this forum. When it came out, it was pretty dark, but not as bad as the transmission. Mine has 173K, and I don't know when the diffs and transaxle fluids were changed. The filter on the tranny was dated 12/2006 so the tranny fluid could be as much as 5 years old.

    Man you should have seen the front diff fluid...more like paste than fluid.
    Jon
    04 Silverado 2500 HD Duramax (LB7) 173K Miles
    97 Passat TDI 200K+ Miles
    00 Passat 1.8 150K+ Miles
    97 Corvette 110K+ Miles

  5. #5
    Join Date
    Mar 2000
    Location
    Loyal WI US
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    10,792

    Default

    I'm a Transynd user. There is non better IMHO. One thing I heard from a very reliable source is that there may be a compatibility issue with DexVI and the older input seals on the Allison. Dex VI is also said to solidify at a warmer temp than DexIII.
    Kennedy Diesel-owner
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  6. #6
    Join Date
    Dec 2002
    Location
    Teton Valley, Idaho
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    1,873

    Default

    Quote Originally Posted by Kennedy View Post
    Dex VI is also said to solidify at a warmer temp than DexIII.
    ???

    Meaning that at colder temps the IV won't flow as well as the III?

    But the Dex IV is a full synthetic (at least as it is labelled at the local NAPA). Does that not mean it has better flow properties, hot and cold, than III? Isn't that why GM says to replace III with IV in the transmission?

  7. #7
    Join Date
    Aug 2003
    Location
    saskatchewan canada
    Posts
    43

    Default

    I have a 2005. when i changed to fluid it was black as well. then changed it on a short interval and it was very dark. later on i had to replace the entire transfer case. the bushing had come loose and was spinning around inside , full of metal fillings and such. if it is very dark i would check it out. cost me over $2000 to get it rebuilt, should have just bought a rebuilt one, but did not reliaze all that was poched on it.
    2005 Silverado 2500HD CC 4X4 5-speed Allison KD transfer case upgrade Reflex Spray in Bed coating, Access tonneau cover, Banks Ottomind 6 Tuner with Power PDA, Banks Monster exhaust,Banks Ram air intake. Ultrastart remote starter,Blistein shocks,Mag-hytech deep trans pan, Pulling 1982 27.5 ft Golden Falcon TT 275,000 kms

  8. #8
    Join Date
    Dec 2000
    Location
    Hawaii/Arizona
    Posts
    259

    Smile Transfer Case Fluid Change

    I am about to change my transfer case fluid for the 5th time in 180k miles. I have always used the GM owners manual recommended fluid GM p/n 12378508. The new/fresh fluid is a blue/green color and a dark dirty motor looking fluid after use. It appears that some DP members are draining the original blue/green fluid that looks like dirty motor after use and replacing it with ATF. Has GM made the determination that ATF is better than the owners manual recommended GM p/n 12378508? I have never had any problems with my transfer case and only want to use the best fluids in my truck. What is the VERY BEST fluid to use in my TC??????????
    Thanks
    John
    *2006 Chevy, 3500, 4X4, DRW, (LBZ) D/A, CC, LT, 252K Miles, 19.5" Wheels, Mag Hytec Transmission Pan and Differential Cover, SS Grill Guard, Racor 2 micron aux fuel filter, 100 Gallon Aux Fuel Tank, using Edge Evolution, Predator Diablosport, Kennedy ECM tune, Fitch Fuel Catalyst.

    *2006 Four Winds, Dutchman, 36', RV, D/A, 5500 Kodiak.
    *1993 Harley Davidson, Turbo charged, Springer Softail.
    *2007 Pontiac Solstice.
    *2005 Jeep, Liberty, CRD (diesel).
    *Full-timing in USA, see America first.

    BUY AMERICAN or CANADIAN, NOTHING from CHINA .

  9. #9
    Join Date
    Apr 2001
    Location
    CA
    Posts
    13,573

    Arrow

    Quote Originally Posted by CoyleJR View Post
    I am about to change my transfer case fluid for the 5th time in 180k miles. I have always used the GM owners manual recommended fluid GM p/n 12378508. The new/fresh fluid is a blue/green color and a dark dirty motor looking fluid after use. It appears that some DP members are draining the original blue/green fluid that looks like dirty motor after use and replacing it with ATF. Has GM made the determination that ATF is better than the owners manual recommended GM p/n 12378508? I have never had any problems with my transfer case and only want to use the best fluids in my truck. What is the VERY BEST fluid to use in my TC??????????
    Thanks
    John
    The part number you posted is the WRONG fluid. That's Autotrac II fluid. It is ONLY for electronic/auto 4x4, which is NOT available on a 2500HD or 3500 GM truck. That fluid is designed and recommended for only 2500 (non HD) and lesser vehicles with auto 4x4. Your 4x4 system is electric, NOT electronic. Your transfer case should be serviced with ATF, the same fluid you should be using in the transmission. I recommend synthetic for both, especially if towing, and absolutely if towing heavy or frequently. The owner's manual covers several vehicle models, and they are not all the same.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  10. #10
    Join Date
    Dec 2000
    Location
    Hawaii/Arizona
    Posts
    259

    Default Correct TC fluid

    DuramaxMaverick,

    I will replace the current fluid with Dexron VI full synthetic.

    Thanks
    John
    *2006 Chevy, 3500, 4X4, DRW, (LBZ) D/A, CC, LT, 252K Miles, 19.5" Wheels, Mag Hytec Transmission Pan and Differential Cover, SS Grill Guard, Racor 2 micron aux fuel filter, 100 Gallon Aux Fuel Tank, using Edge Evolution, Predator Diablosport, Kennedy ECM tune, Fitch Fuel Catalyst.

    *2006 Four Winds, Dutchman, 36', RV, D/A, 5500 Kodiak.
    *1993 Harley Davidson, Turbo charged, Springer Softail.
    *2007 Pontiac Solstice.
    *2005 Jeep, Liberty, CRD (diesel).
    *Full-timing in USA, see America first.

    BUY AMERICAN or CANADIAN, NOTHING from CHINA .

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