2003 GMC Envoy, 4wd issue

2003 Envoy with AWD. If it’s in 2wd there is no issue. AWD, no issue (though nothing engaged either). In 4wd Hi or Lo going straight forward or straight back it’s fine. However in 4wd Hi & Lo, and you turn, there being the troubles.

A soft turn is ok, say on a highway, a long slow turn would be fine. As the turn gets sharper, resistance begins and esculates with the sharpness of the turn.

So in a local parking lot, just moving in a straight line along at idle speed, if I turn medium, resistance will build, you can feel the Envoy get “heavy” but without touching the accelerator, the Envoy continues to move. You just feel the drag, or resistance.

Now moving in a straight line along at idle speed, if I turn sharp, resistance will build quickly, I hear a “click” and the Envoy stops, say in about 6-8 ft. Now at this point I can keep the turn where it is at, put it in reverse and it will be free, for around another 8-10 feet when I hear a “click”, and the Envoy stops again. I can then put it in D, go forward freely for around 8-10 feet and “click” Envoy stops. I can repeat this pattern over and over until I run out of gas or the cops come get me due to the owners of the parking lot believing I’ve lost my mind. This process is the same turning left or right, forward or backward.

Again if it was in 2wd I can go in circles all day without any issue, or I get too dizzy and pass out.

So… the issue seems to be in the front transfer box, but what? What is it that moves that would cause such a problem? Any ideas?


I believe a 2003 Envoy has the Autotrac system. The 4wd Hi and and Lo settings should not be used on dry pavement as driveline binding will occur. This is what you are describing. This is normal for a part time 4wd system.

The Auto 4wd setting engages the transfer case, but does not engage the front axles until slippage is detected at the rear wheels. This enables Auto 4wd to be used on dry pavement with a slight decrease in mpg.

A better explanation of the system will be in the Owner’s Manual.

Ed B.

Generally speaking you shouldn’t be using 4HI or 4Lo on any paved road that’s not covered in snow/mud/dirt. Doing so will cause the drivetrain to bind up because the center diff is locked and there’s too much traction of the surface of a dry paved road for the wheels to slip when you make a turn. When the center diff is locked the front wheels and rear wheels have to turn at the same speed, which is problem when you make a turn since the wheels on the outside of the turn will turn at a different rate or speed than the wheels on the inside of the turn.

What you are experiencing sounds like the drivetrain binding up. The solution is not use 4Hi or 4Lo on pavement. This 4 wheel drive 101 stuff.

I exercise the settings on a regular basis, but even towing a boat out of a sand launch have found auto to be juxt fine. Never had to go other than auto even with the 26" snow last year. 03 trailblazer

What you are experiencing is perfectly normal considering you are using your 4WD settings outside of their design parameters. If you keep using the system this way, you will break something that will be in the range of expensive to extremely expensive to repair, and are currently causing premature wear of all the components in the 4WD system and drivetrain. 4HI and 4LO are not designed to be used on pavement or any surface with semi-reasonable traction, only for snow and ice covered roads (NOT if they have already been plowed and salted), mud, and if you have already gotten stuck and need additional traction to get un-stuck. General rule of thumb: if it looks like a road, do not use the 4HI or 4LO settings. They are generally considered off-road-only settings. If you read about your 4WD system in your owner’s manual, it will tell you the same thing.

You are not alone in this misunderstanding, though. I had a customer once bring in a 4WD Chevy truck with a brake complaint. Two minutes into the test drive, I felt the drivetrain binding up, looked at the transfer case stick, and noticed it was in 4WD. I returned to the shop after shifting out of 4WD and took the customer on another test drive and asked if the problem was present, which it wasn’t, then spent the next half hour trying to explain why you cannot drive around in 4WD all the time.