I'm wondering if anyone knows what the factory used to fill the t-case in my '06 GMC Sierra 2500HD Dmax/Allison? It has the push button (dash) 4x4- 2HI, 4HI, 4LO.

Anyone?

Thanks!

Matt

The recommended GM replacement fluid for TC's is Auto-Trak II Transfer Case Fluid - GM part #12378508. It's blue in color and cost close to $10/quart from the stealer.

autotrack is for the 4 position cases found in the 1/2 tons. the hds have auto trans fluid in them if i recall.

autotrack is for the 4 position cases found in the 1/2 tons. the hds have auto trans fluid in them if i recall.

My owners manual for my '05 2500HD calls for Auto-Trak II in an Automatic Transfer Case and Dexron III TF in the manual and all-wheel drive TC's. I'm in the process of replacing my transfer case (NPG 263XHD) with a reman unit from member SoGrand and his shop said I had to use the Auto-Trak II for them to warranty it. I ran it past my local GM dealer when I went to buy it and they said the same.

If there's a warranty I'd fill with whatever the General says to fill with. Since my truck long since has no warranty I use ATF just like the trans and have no issues

My owners manual for my '05 2500HD calls for Auto-Trak II in an Automatic Transfer Case and Dexron III TF in the manual and all-wheel drive TC's. I'm in the process of replacing my transfer case (NPG 263XHD) with a reman unit from member SoGrand and his shop said I had to use the Auto-Trak II for them to warranty it. I ran it past my local GM dealer when I went to buy it and they said the same.

in your owners manual when they reference automatic transfer case they are refering to the np8 case, which is not found in the 6.6. the 3 position case requires atf according to the owners manual and calls for manual trans fluid in our service manuals for p/n...88861801 for canada and 88861800 for u.s.

But then in 07 classic, same case, the owners manual and service manual call for the manual transmission fluid p/n as listed above.

remember when this was simple..lol..

The recommended GM replacement fluid for TC's is Auto-Trak II Transfer Case Fluid - GM part #12378508. It's blue in color and cost close to $10/quart from the stealer.

Isn't auto trak a tcase that has an awd mode?

yes, its a np8 case, it has clutches that apply as required, its in the 3/4 ton subs and light trucks. as a option. it has 4 switch position, auto,4hi,2hi,4lo.

My owners manual for my '05 2500HD calls for Auto-Trak II in an Automatic Transfer Case and Dexron III TF in the manual and all-wheel drive TC's. I'm in the process of replacing my transfer case (NPG 263XHD) with a reman unit from member SoGrand and his shop said I had to use the Auto-Trak II for them to warranty it. I ran it past my local GM dealer when I went to buy it and they said the same.

263s are all "manual shift" cases regardless of being push button or shift on the floor and call for dexron III ATF. The GM blue stuff has a friction modifier in it for the clutches that the 246 auto trac cases have. Not to step on anyones wiener, but i would not buy from a company that wont warranty a T-case that is filled with the manufactures recommended fluid, which in this instance is ATF in an NV 263

in your owners manual when they reference automatic transfer case they are refering to the np8 case, which is not found in the 6.6. the 3 position case requires atf according to the owners manual and calls for manual trans fluid in our service manuals for p/n...88861801 for canada and 88861800 for u.s.

But then in 07 classic, same case, the owners manual and service manual call for the manual transmission fluid p/n as listed above.

remember when this was simple..lol..

It is simple, 263s require ATF, even if most dealers are too stupid to know that.

I stand corrected, I made some calls to some other folks today and they are all agreeing with what you guys say now - only they recommend synthetic ATF. Go figure....

So the three button is just a fancy floor shifter control? That's nice.

My owners manual for my '05 2500HD calls for Auto-Trak II in an Automatic Transfer Case and Dexron III TF in the manual and all-wheel drive TC's. I'm in the process of replacing my transfer case (NPG 263XHD) with a reman unit from member SoGrand and his shop said I had to use the Auto-Trak II for them to warranty it. I ran it past my local GM dealer when I went to buy it and they said the same.

I stand corrected, I made some calls to some other folks today and they are all agreeing with what you guys say now - only they recommend synthetic ATF. Go figure....


Well, to get right down to it and split hairs, the underlined portion of your statement is 100% correct, but the 263 is not an automatic transfer case. To be fair, SoGrand is probably just regurgitating the information he received from an ignorant dealer.

I asked this same question when i changed mine a while back. Even asked dealer and they said autotrac. Knowledgeable people on here said atf. Mine had never been touched so what ever the factory put in it was still in it. It was the ATF.