-01 tahoe strange 4hi sounds

[daol]

4 auto uses clutches in the tcase so the front can be disengaged/engaged automatically. In 4wd the front axles are engaged the whole time and there is no slip within the tcase for the front.

Hmm ok, so could the that difference cause sounds from the front wheels while in 4hi, and not in auto, even if the front tires are working?

Had the front dif drained, nothing strange.

 

[rockola1971]

it sounds like you arent use to 4wd vehicles. Its is quite normal for a 4wd to make some noise that would make a person that has never had a 4wd think there is something wrong. When turning from a very low speed and especially when sharply turning you will hear some fairly loud noises. Its even more pronounced on totally dry pavement and ground. If it doesnt do it in 2wd and it doesnt do it at moderate speeds (above 25mph or so) then I wouldnt worry about it. Might get someone that is familiar with 4wd and have them take a ride with you to make sure.
When you are in 2wd your front axles are turning but are NOT being driven by the Tcase/Front Dif. So its likely that they are ok. When in 2wd your front driveshaft is disconnected from the tacase(internally) and your front differential is not locked to the front axles either. In 4wd auto your Tcase senses slip and engages 4wd all by itself. I would check your fluid level on your tcase since that is a smart habit to get into atleast once a year if not 2 or 3. There are tons of us here that are quite familar with our setups so there is no such thing as a dumb question. When I was 15 I couldnt of explained to you how a tcase even works if it meant my life. Now I rebuild my own.

Edited to correct 2wd description. (mislabeled as 4wd)

 

[daol]

it sounds like you arent use to 4wd vehicles. Its is quite normal for a 4wd to make some noise that would make a person that has never had a 4wd think there is something wrong. When turning from a very low speed and especially when sharply turning you will hear some fairly loud noises. Its even more pronounced on totally dry pavement and ground. If it doesnt do it in 2wd and it doesnt do it at moderate speeds (above 25mph or so) then I wouldnt worry about it. Might get someone that is familiar with 4wd and have them take a ride with you to make sure.
When you are in 2wd your front axles are turning but are NOT being driven by the Tcase/Front Dif. So its likely that they are ok. When in 4wd your front driveshaft is disconnected from the tacase(internally) and your front differential is not locked to the front axles either. In 4wd auto your Tcase senses slip and engages 4wd all by itself. I would check your fluid level on your tcase since that is a smart habit to get into atleast once a year if not 2 or 3. There are tons of us here that are quite familar with our setups so there is no such thing as a dumb question. When I was 15 I couldnt of explained to you how a tcase even works if it meant my life. Now I rebuild my own.

Thanks for the great answer
I only had and car's before, not real 4wd, and since I had the fluids looked at and changed, an everything looked good, and since I only have the sound from 12 mph and below in corners or braking to a standstill, ita most likely just me not being used to this type of 4wd, I thought that could be the case, but I rather ask, and drive and have a breakdown

 

[Fless]

If you want a bit of in-depth info on how the Auto NVG246 Tcase works:
http://www.atraonline.com/gears/2006/2006-07/2006_07_10.pdf