I have a 97 Tahoe with the GT4 (3.73) option and my gears are very loud. When you accelerate, even very slowly, you can here a moderatly loud grinding noise. The rear end has plently of fluid in it, I checked that. The gears also have a very loose mesh and I can turn the pinion a pretty good bit.

 

Would changing the fluid help any, cause it could be full of pieces of metal from the gears wearing. Hmm....can I just remove my carrier and pinion and add another shim to get me by for a lil while longer. After I have the pinion bearing pressed off of couse.