I have a 2000 Z-71 Silverado and everytime i put it in four wheel drive it makes an awful grinding noise. When trying to turn inot a parking spot the axle feels like it is rubbing metal on metal and the truck lurches. When not in four wheel drive there are no weird noises. My local mechanic says that 4X4’s are just nautrally noisy and the Chevy dealer says noise comes from the high mileage of the vehicle (around 100,000). The local 4X4 shop wants $75 an hour just to look at it. Any suggestions???
Are you putting it in 4WD on DRY PAVEMENT??? Sounds like you are. If you are DON’T.
When turning are you on mostly dry pavement? If so this is simply an absymal quality of 4wd, if you have done this a lot in the past(4wd on dry pavement) you may have some loose parts in the drivetrain that getting noisy when under high strain.
Also are the four tires on the vehicle matched in wear, size, make and model?
There is an axle disconnect on the passenger’s side of the differential that has to engage when you shift into 4wd. The electric actuators for the disconnect are prone to failing, so the splines are probably not fully engaging. I would start there. There are also kits available to manual operate the disconnect using a cable and lever routed into the cab. I think JC whitney sells them.