Specific Differences Between Autotrac 4WD and AWD Systems?

[Justinj360]

I have a 2004 GMC Yukon 5.3L AWD with Stabilitrak. My truck is missing the round Auto 4x4 button and only has a Stabilitrak button and a 4LO button. I know the difference between 4WD and AWD, I'm not a simpleton. But what I don't understand is with my truck is it always in 4WD or is it in 2WD the whole time until it senses slippage? Also, what is the power split? Is it an even 50/50?

Also, on my vehicle spec sheet it says there is a locking rear differential. That must be automatic, right?

 

[UrbanSuburban]

If I remember right, the normal driving is done in awd but with 90 percent to the rear and 10 to the front. When the slip is detected then it will adjust as needed. The stabilitrak is really just to prevent the truck from going out of control within the bounds of physics, it uses the abs and other senors such as yaw and the steering wheel position to keep you in control. As for the Rear Diff, look in the glove box for the G80 option and that should tell you which one you have, the other was G86 that was controlled by the brakes.

 

[rockola1971]

The rearend is probably a limited slip locking differential. In that case there clutches in the rearend. My 99 Sierra Z71 has it. Had to rebuild it because of a bad axle tube bearing but the clutches dont last long and while I was in there it got new clutches. The look like miniature brake pads.

 

[swathdiver]

Can you post your "N" codes and tell us how many buttons for the drivetrain are on your dash?

 

[Justinj360]

Can you post your "N" codes and tell us how many buttons for the drivetrain are on your dash?

What are these "N codes" you speak of? I listed the buttons in the original post. There's 3 of them.

 

[swathdiver]

Your RPO codes. It tells us which transfer case you have. On the GM Heritage Center website, you can download the book for your year or close to it truck. In the pdf will be detailed explanation of the different transfer cases and drives along with diagrams and such. Several fellas with the same 3 buttons have come on here and asked, I should remember by now!

 

[D is for DENALI]

It will say something like nr3 , np8 or nr8...