2005 Tahoe Z71: I've noticed a noise from under the truck when I use the Auto 4WD button as I decelerate and coast to a stop. It resembles the noise or hum of knobby tires on a smooth paved surface. Putting it back to 2WD eliminates the noise. Any ideas? Thanks in advance. John

2005 Tahoe Z71: I've noticed a noise from under the truck when I use the Auto 4WD button as I decelerate and coast to a stop. It resembles the noise or hum of knobby tires on a smooth paved surface. Putting it back to 2WD eliminates the noise. Any ideas? Thanks in advance. John

you will damage the 4x4 when you drive on solid dry pavement...your noise is common when driving on solid dry pavement as the front axle is locked in auto 4x4....if the front tires are at different wear points this is bad..also...

if you have been operating the vehicle often on this dry pavement in 4x4 you best replace the transfercase fluids and front diff oil..

I have the same thing in my 05 Yukon - when I'm decelerating (or accelerating) and I have it in Auto 4wd, I get a humming or whining noise from what seems to be the front differential. I have read elsewhere that this is common, but I have also heard others say that there was something wrong causing the problem. I don't know what to believe.

Also, if I recall correctly the owners manual says that the auto 4wd mode is perfectly fine for any type of driving, as the front wheels only engage as necessary.

when you are in auto 4x4 the front axle is locked....both front wheels are one....this on dry pavement is BAD.....

if you are driving in a heavy rain or snow storm use auto 4x4....
If you are plowing/towing boat out of water on a slippery steep ramp put in high 4x4 or low 4x4....this is some examples...of use..

Check the tire sizes too,all have to be the same size.My father bought a 2001 and it had that noise,left front tire was a differant size than the other 3 tires.It could be in the differantal too,a bad bearing.