Water in front differential

check the tail shaft for failed "u" joints

Yes, Rebuild the differential BEFORE it leaves you on the side of the road!!!!!

You have a worn or damaged CV joint. Your local service professional should be able to verify diagnosis. Have your ball joints and entire front suspension inspected also.

Sounds normal for 4HI operation on dry pavement. The driveline is binding 'cause every wheel needs to turn @ different speeds on a turn and can't. Shift to 2wd or Auto

actually, it's most likely a differential problem. if the pinion or worm gear id missing a spur, it will vibrate and grind until enough oil covers them to stop the friction...usually after 10 min or so. what they will do is use a micro lubricant that seeps into the metal to keep it lubed up even when the oil has settled to the bottom of the case, this will at least quiet the grinding for those 10 min or so until the inevitable happens and the gear shatters because of vibration, wear, etc.
if its in the front, youll still be able to drive, but only in 2WD and you will hear a loud grinding/rattling, very unpleasent sound, from the front end. have them open up the case and look at the gears instead of assuming, its 10 bolts for gods sake so they need to do their job and WORK! dont let them toss you aside, tell them what you want...sometimes thats what it takes.

If 4wd Tahoe, it is the CV joint going out or is out, replace part about 250 bucks, very common in 4wd Tahoe

Are you under warranty? Make it the dealers problem if its eligible.

If the front hubs are grinding regardless of being in 2wheel or 4wheel drive it can be the hub bearings which turn regardless. If it grinds only when in 4x4 then the wheel shafts or differential or front driveshaft or transfer case is making the noise because all of these parts move when in 4wheel drive.

oil and air filter every 3 mo or 3000 miles which ever comes first the timing belt needs to be checked really soon and you might consider taking it to the dealer for a transmission flush filter and fill. the dealer can set you up with the best intervals to do the major maintenance.

The dealership is trying to get out pf paying for the problem. I'm not going to say this is a common problem but it does seem to happen a lot. The axle seals leak quite frequently also the pinion seal leaks.There might be also be a problem with the vent, the hose could have came loose or hole in it. There is also an oring seal around the filler hole that may not have been installed properly.

If the dealership fails to help you call the GM customer assistance center and lodge a complaint. Chevrolet Customer Assistance Center 1-800-222-1020

NO! This is a Ploy to Screw you for Cash! They should not need attention at all until 100,000 Miles unless something goes Wrong.