im hearing a strong grinding noise from the left front of my truck what is it on 2003 Chevrolet Avalanche 1500

im hearing a sound like gears grinding together in the front of truck on drivers side, and i can hear that something is loose, i looked but didnt see anything wrong. but it sounds like clinging, like the wheel is loose ,and the grinding isnt constant if i stop it will stop but sometimes upon take off it starts grinding again. like some thing is loose or broken or trying to engage while driving. also having problems with 4 wheel drive .it says service four wheel drive in the instrument cluster could that be part of the problem or the whole problem?

To many possibilities, needs to be seen to tell, get a mechanic to check it out.
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np
1 more answer
seek diag and est from a frt end shop. could be hub bearing,shocks,tie rod ends or several other issues