What's the difference between 4WD and Auto. In AUTO, does the vehicle engage 4WD when it senses slippage?

 

dont quote me but i believe so

 

I think that is correct! However, I have a question about this! I have yet had my Tahoe in 4x4 or has it ever engaged.

Do you feel it engage when it is in auto? Is it instant?

Secondly, when shifting out of 4x4 into 2wd how long does it take to disengage? Is it a length of time, or a certain distance the wheels have to travel? Like all vehicles it seems to take time.

It sucks when drive to work in 4x4 and park it. Then when leaving snow is melted or gone and you take it out of 4x4 however when backing out and having to crank the wheel it feels like you are going to lose your front end! NOTE: this was in previous vehicles, I havent taken my 07 tahoe out in the snow yet!

 

Once in 4wd going back to 2wd I had to travel a couple of hundred feet before it disengages; yes, when it is in 4wd on dry pavement unless you make very slight raidus turns you will get the "somethings going to break" feel as if you were trying to drive over a curb. I only used 4wd once.......

 

The feeling of the front end dragging is exactly that. When in 4WD the front differential is engaged. Driving straight is no big deal but the differential does not allow the front wheels to turn at different speeds. When turning, the outside wheel goes faster than the inside. Since it's locked it drags. Before making these turns you should take it out of 4WD.

In AUTO mode I have never felt anything different which is why I was wondering if it was engaging in slipping conditions. I know I've gotten on the gas in the snow when in AUTO but never felt a thing change. Just smooth I guess.

With all the snow lately in Chicago I've been in 4WD and AUTO more than 2WD. Fun though, great truck in the snow.

 

NEVER engage "4WD" on dry pavement, it will damage components and there is no reason to.

In "AUTO" mode the transfer case is locked up and the front differential is put in a "stand-by" mode, the wheels speed sensors then compare the speed of the front tires (taking into account variances during turns via the steering angle sensor) to that of the rear tires; as soon as one of rear tires speed exceeds a predetermined % of the front then the differential is engaged, the system cycles at a sample rate of 100 times per second so the transition is normally seamless.

 

Know-it-all

Thanks ZX, You are my online manual.

 

I have always taken the 4x4 out when on dry pavement. But say you have to park the vehicle in lot and that when you parked it was in 4x4 because of 10 inches of snow! When you leave that night the parking lot is cleared and now dry payment behind your vehicle. You back out, very tight lot, so cranking the wheel is a must. That was my example. I know to not make the turns on dry pavement in 4x4, but it seems to take so long to disengage, All vehicles not just the tahoe.

 

Thats crazy, so much technology on/in todays vehicles.

 

And that was the much simplified (condensed) version.