Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Because I work in a shop, I would put the truck up in the air and try to see if I could pinpoint the noise with the vehicle running in four wheel drive. I hesitate to tell you to do the same. If you have access to 4 good jack stands, then by all means, try this. If you don't have the jack stands, it will be difficult to find something like this. You could remove the front drive shaft and inspect the ujoint in the front and the cv joint at the rear of the shaft for play, or damage. While the shaft is out, you could try driving it and see if the noise is gone. If it is gone, it is probably the shaft, but could still be something in the front differential or the tcase.
The best way to diagnos this is up in the air with the system running.
I wish I could tell you more, but you will have to narrow down the source of the noise first before we can tell you how to fix it.
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