Auto 4wd Engaging

Mossyoakglock · February 10, 2011

Tonight on the way home I had to use Auto on the side roads and interstate due to the snow and ice we got. When I got home I decided to play around a bit in the neighborhood. When I was finished I put it back in Auto and felt it kick in. It was a pretty loud clunk and noticable thud. Is this normal?

Also, I turned off Stabilitrak and Traction Control and when I started to spin it felt like the systems were still kicking in a bit. I don't think I could have done and donuts because of this either. I don't think the system would have let me. Is this normal as well?

pilsner · February 10, 2011

Where you on the throttle while it was engaging?

I always try and stay off the throttle while switching; however, one time I did dig in a little too quick and heard some horrible clunking.

music · February 10, 2011

Every once in a while... yes. Normal. Every time? No

Mossyoakglock · February 10, 2011

I was on the throttle but once I felt it engage I backed off.

Also, is it better to have both Strabilitrak and Traction Control off when driving in snow/ice or just Traction Control off?

00Silverado4x4 · February 11, 2011

Don't know about the GMT900 but my old 800 will make some clunking if rear end is already spinning & trying to engage Auto or 4x4. Don't think you have a problem, the truck is just trying to do what it's designed to. I just make sure I left off the gas completely before engaging, even if I'm not spinning. Now on my old Sonoma I had I once engaged 4x4 with a good bit of gas applied...now that make some real racket you never want to hear out of the truck. Sounded like going from Drive to Park while driving 55 down the road. Yes I did that too but it was my sister's car that was a real piece...

uh6tdrvr · February 11, 2011

Depends but if you have TC off and Stabilatrac on it will keep you driving straight. Id say to Keep it on!

Z45 · February 11, 2011

The owners manual states some noise is normal operating conditions. Lots of loud noise usually means its being driven aggressively.

I am driving around on snow and ice all the time, I never disable TC or stablitak, my truck has been in AUTO since early Dec. The only time I might consider that is if I am stuck or need to pull someone out where I don't want the system to compensate for the spinning wheels. TC is supposed to stop the wheels from spinning w/o traction so disabling that only lets the wheels with no traction spin uncontrollably.

I don't hear any unusual noise with my AUTO engages unless I am spinning the tires hard. If the rear wheels are spinning and the fronts engage, there is bound to be noise from the sudden jar to the drive train.

Owned and driven 4x4's since the 1970's..

KMGZ400 · February 11, 2011

the 4x4 systems will always make some diffrent weird noises when your playing around or driving, if i always makes the same noise, its most likely a problem, but if its just every once in a while, dont worry about it

pilsner · February 11, 2011

I turn both TC and stabilitrac off. Usually all the time. Whether its deep snow or I'm on site and it's muddy.

It gives me the piece of mind that I'm controlling how I get through it, not my truck.

on the highway though, they;re both always on.

Nargg · February 11, 2011

Check out your owner's manual. It specifically states that you may hear a "clunk" when the gears engage. Also, I'd stay off the gas when switching. Specifically, the owner's manual says to be in neutral and still or rolling only 2 MPH when changing the transfer case gear selection.