GM Transfer Case Fluid

[hk33ka1]

I e-mailed Amsoil's tech center and asked what fluid is recommended for the transfer cases in Sonomas, Sierras, Suburbans etc. from the 70's, 80's, 90's and up. I figured their ATF would do, this is the response:

"If these are manually shifted transfer cases, then our AMSOIL ATF is an excellent choice. If they are auto, then GM requires AutoTrac fluid and we do not have a replacement for AutoTrac"

How are the two types of transfer cases different? I think Amsoil would be the last company to tell you not to use their own product unless they really mean it. I have run Mobil 1 ATF in the transfer case in my auto 84 GMC truck for a long time and have not had any problems, but then again a lot of people use Slick 50 without any problems too? Any idea on wether or not to use ATf in auto tranny transfer cases or not especially in late model trucks, and if not what other than OEM fluid would work.

 

[MolaKule]

I use Schaeffer's 204S ATF in my transfer case for the '92 Burb 4X4 which is manually shifted. I have had excellent results.

I know very little about the AutoTrac, but I suspect it has special clutches that need a fluid with the precise amount of friction modifiers.

[ January 16, 2003, 11:30 PM: Message edited by: MolaKule ]

 

[RobZ71LM7]

The autotrac transfer case has a clutch in it and needs the special GM blue fluid. Originally the Autotrac trucks came with Dexron III ATF like conventional GM transfer cases. However they had a bad habit of clunking so GM issued the blue fluid to fix it. I can get you the part number if you like. The fluid is not very expensive.

 

[Mike_dup1]

I had the clunking problem in my 1999 GMC K1500 with Auotrac. It did not have ATF in it but they said it was something similar based on ATF with additives. The fix was to use the AutoTrac II blue fluid, but first the old fluid had to be completely flushed out by changing it 2x. Some were having problems with dealers and others installing ATF in it because the original AT fluid looked similar to ATF.

Its a proprietary GM product and so far no one has come out with a product to replace it. GM must hold the patten on it or something. I called GM powertrain and they would not tell me what else I could use. Just said it requires this AutoTrac II. It mades in Canada.

[ January 17, 2003, 09:28 AM: Message edited by: Mike ]

 

[RobZ71LM7]

Personally I think they're full of it b/c I know of several original autotrac owner's with manuals that say use DEXRON III ATF.

 

[MolaKule]

"Just said it requires this AutoTrac II. It mades in Canada."

Sounds like a PetroCanada Group III product.

I would seriously try the Schaeffer's 204S Dexron III. It has one of the better additive packages on the market, and it is a synthetic blend.

 

[Mike_dup1]

I have an extra quart right here.

quote:

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AUTO-TRAK II Transfer Case Fluid
Part No. 12378508

• For four wheel drive vehicle with automatic transder case
• Withstands extended high temperature operation
• Improved oxidation resistance

Says it contains a misture of petroleum oils and performance additives.

CAUTION! Prolonged contact may cause skin and eye irratation. Avoid skin and eye contact. This product does not present an inhalation concern at ambient but avoid breathing vapors, mists or fumes of heated oil. Wear protective gloves when handling.

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[ January 22, 2003, 05:08 PM: Message edited by: Mike ]