Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
I am sorry your having this problem
most of the time when you hear a noise or feel a vibration when you let off the gas there is a bearing or issue inside the transfer case and or rear axle
usually the best action to find out which it is would be to run the truck up in the air and listen for the noise
usually you can hear it and pin point it to know if its a bearing inside the rear axle or transfer case
the odds are there is a pinion bearing or axle bearing starting to fail or possibly a u-joint
but most of these with this kind of noise are in the rear axle
how are you making out ?