on demand 4wd

[builderpaul]

Anyone have a GMC 1500? The on demand 4wd sounds like what my wifes subaru uses. It is a great system, if it is. Is this available on a chevy?

 

TIA

[RyanbabZ71]

chevy has autotrac but you only want to have it on if the roads are somewhat slick. You dont want to drive around with it on on dry pavement

[Tweeter400]

I have Auto 4WD which transfers power to the front when it needs it. I use it in the winter and I love it. Works good in the rain too!

 

[builderpaul]

So auto trac is the chevy version, and you can turn it on and off? I guess itisn't like a suburu than. I know there is a way to lock it so it is like the traditional part time 4wd, but didn't know it can be turned off. Is there another lever on the floor or is it electric? I really should get to a dealer more often to checkout these new fangled contraptions.

[Shaners]

AutoTrac is electronic and there is a button on the left side of the dash to activate it. There are also 4-hi and 4-lo options along with 2-hi.

 

There are a few GM trucks that have "All Wheel Drive" like the C3 and SS models. This is a permenant system that is always on.

[GnatGoSplat]

The AutoTrac 4x4 is not really like the Subaru VDC AWD system.

The Auto4x4 is either ON or OFF. When ON, the transfer case locks. Front and rear differentials get an even split 50/50 power.

The Subaru VDC is fulltime AWD with electronic controls to redirect power.

It's probably more similar to the fulltime AWD system used in the 03 Suburban with traction control, H2 Hummer, and 03 Cadillac Escalade. Those systems use an open transfer case so the rear gets 60% and the front gets 40%. Electronic controls actively brake the wheels that slip so that power can be redirected to the wheels with traction. The H2 and maybe even Suburban have extra functionality in that the transfer case can be locked and also offers 4LO modes.

 

The Silverado SS, Sierra C3, and Sierra Denali use viscous coupling AWD which is basically a mechanical, non-computerized AWD system that can vary the amount of power front/rear depending on which wheels are slipping.