AutoTrac --Auto Setting Question

TxDoc · February 26, 2003

When you are running along in Auto 4x4 and the system engages the front end, there is no indication on the dash or anything? Correct?

I can tell the difference in 2WD HI and the Auto setting, but just wondered if you can feel or hear anything as it kicks in and out.

We have been getting sleet, freezing rain, snow and "thunder sleet". The truck and the Michelin LTX AT's do great, I did use the SSC cable chains as the ice needs something to bite into it.

jr.parrish · February 26, 2003

You are correct, there is no indicator on the dash. Since yours is a 03 a message may flash on the DIC, some thing like "Traction Active". Our 03 Yukon Xl Denali does that, but its a AWD with "Stablity Track", so it may be different.

On my Silveado, I really can't hear anything or feel, apart from the added traction on launchs or slippery conditions, anything different than when in 2 HI.

carguru · February 26, 2003

The only thing I can hear is the low rumble of the transfer case when the Auto button is on. Other than that, the only differences between 2wd mode is slight tire scrub in low speed tight turns and the ability to launch hard on wet pavement without wheelspin.

The operation is pretty seamless as it goes into and out of 4wd.

99silveradoz71 · February 26, 2003

I just hear slight powertrain noise if I launch hard on a slippery surface in auto, but as for the transition when it detects slip, it is seemless.

Z71GUY · February 26, 2003

I have a quesiton about Auto 4wd. Is there a MAX speed that you can drive while in this mode? I know 4hi has a max speed, but when I am on secondary roads then jump on the highway for a bit (that have some snow on them), can I keep it in Auto for highway speeds?

Thanks,

Eric

c4cruiser · February 26, 2003

I have a quesiton about Auto 4wd. Is there a MAX speed that you can drive while in this mode? I know 4hi has a max speed, but when I am on secondary roads then jump on the highway for a bit (that have some snow on them), can I keep it in Auto for highway speeds?

Thanks,

Eric

I have run at speeds approaching 65 on freeways in auto mode when headed toward ski areas. I'll usually hit the auto switch just before I get to snowy or rain/snow conditions or if the outside temps are below 28 degrees or so with the pavement wet or slush.

Freeway speeds on I-90 over Snoqualmie Pass in WA are changed on electronic signs by the state patrol as road conditions change so I would very seldom see any speed much over 65 anyway.

My 99 owner's manual does not specify a speed at which you can or should switch between 2WD or auto.

Z71GUY · February 26, 2003

Thats about the fastest I ever drove with Auto engaged. I usually keep it around 55mph...I just dont feel right going that fast with part of the 4wd system engaged and the fact that the roads are kinda slick. Just wondering if there was an official number from GM though...