High mileage Transfer case fluid

[IH784]

I’ve got a Silverado with 169,000 miles on it. To my knowledge the transfer case fluid has never been changed. I’ve read it’s bad to change or flush the transmission fluid with this many miles. Would it damage anything to change the transfer case fluid? Ie: break crud loose or gum up something?

[stevejones]

No worries.  Get the right fluid for your application, drain, refill, and drive happy.

[apollo18]

nah transfer case will be fine! go with a high end product like royal purple amsoil red line etc

[IH784]

Sweet! .  Thanks you two! Really fast response time. 

[BlancoSilverado]

Transfer-case and transmission are different (sometimes uses the same oil).

Just swapping out the oil will be better for it. 

[Black02Silverado]

No problems at all.  Just curious but when you do drain it let us know how it looked. 

[Colossus]

Make sure you use the right fluid.  If you have the autotrac (2 Hi, AWD, 4WD, 4-LO) then you use fluid for autotrac.  if you don't have an AWD option on your transfer case, just 2WD, 4Hi and 4Lo then you use ATF in the transfer case.  I now recommend the Amsoil products for the transfer case and front and rear diff. 

Edited July 22, 2020 by Colossus

[newdude]

Since I don't see your year/make/model mentioned...

 

1999-2006 and 2007 classic with the regular 4x4 manual or electronic shift case use GM Manual Transmission and Transfer Case Fluid, p/n 88861800.  It is a Dexron III fluid, so any Dexron III ATF can be used.  Dexron VI fluids are NOT compatible with these cases.

 

1999-2006 and 2007 classic with the AutoTrak transfer case (has the AUTO button on the switch) use AutoTrak II fluid, p/n 88900402.  No other fluid should be substituted on these cases.

 

If you have a Silverado SS with AWD, those use GM Manual Transmission and Transfer Case Fluid, p/n 88861800.  It is a Dexron III fluid, so any Dexron III ATF can be used.  Dexron VI fluids are NOT compatible with these cases.

 

2007-2014 all transfer cases use Dexron VI.

Edited July 22, 2020 by newdude

[IH784]

It’s a 2005. With a manual 4wd. I read in several places that the 6 is compatible with the 3. Is there a manufacturer’s reference that is available?

Edited July 22, 2020 by IH784

[davester]

While DexVI is considered compatible with DexIII, when I rebuilt my transfer case as part of upgrading my truck to 4wd, I was told that some people had problems with seals leaking in their transfer cases when they put DexVI fluids in them (for GMT800 trucks).  And I know for '06 (I bought a'06 2500 as a parts truck for the 4wd system), GM spec'ed DexVI for the transmission, but still wanted DexIII for the transfer case.

 

I found some Mobil1 transmission fluid that said it was DexIII, and it seems to be ok...

[IH784]

thanks newdude!

Edited July 23, 2020 by IH784

[Black02Silverado]

If you are interested.  AMSOIL's ATF fluid is recommended for your transfer case.  Depending on what T case you have it takes 4 or 4.4 pints.  Basically 2qts to just over 2qts.

 

 

[Colossus]

Go with that stuff. 

[elcamino]

On 7/22/2020 at 10:46 AM, IH784 said:

I’ve got a Silverado with 169,000 miles on it. To my knowledge the transfer case fluid has never been changed. I’ve read it’s bad to change or flush the transmission fluid with this many miles. Would it damage anything to change the transfer case fluid? Ie: break crud loose or gum up something?

Don't listen to anyone who says to leave the ATF in the transmission for the life of the trans. Change your fluid.  People who do change their fluid and have the trans crap out are either just running into bad luck, or their transmission was on its last legs already.  Maybe they thought changing the fluid was going to save it. 

[IH784]

Hey guys, 

 

got it changed. Nothing too unusual. Just really dark red lol. I didn’t use the full two quarts. I was lacking exactly 4 ounces from having both quarts in the transfer case. Is this usual? Ground was “pretty” level and it dribbled out the fill hole. I ASSume the 2.0 quarts is for an initial fill? I used GM P/N: 88861800 as this is the replacement for dexron III. As per @Newdude. Thank you for the heads up again. 

Edited July 25, 2020 by IH784