03 silverado drivetrain issues
 

ill start from the beginning to save confusion as i dont wish to waste anyones time and help is greatly appreciated..i recently had a new transmission put in and transfer case cases broken apart and resealed. afterwards i still had a clunk front drive to reverse so proceeded to change the u joints as they never were done before. after replacement of the ujoints i had a vibration coming from the rear of the truck at around 50+mphs. i took it on a ride on the highway shortly after replacing u joints and all the sudden there were weird squeeks and dragging noises and alot of vibration... almost like i hit a plastic bag.. no debris found or anything.. ive isolated the sound to the drivetrain as it is not coming from the engine while parked.. now there are sounds indefinetly even at slow speeds.. someone please help with where this may be coming from.. im thinking transfer case.. thanks guys.. you are the ones that help keep hard earned money in the pockets of people in need.

before you go overboard. check your tires, you may have a bad tire, separated tread or imbalance issue.

If you have a "rusty hinge" or "bedspring" style squeal at parking lot speeds, combined with other noises and minor handling difficulties, have your hub bearings checked.

What is the mileage on your truck? This happened to my '04 at about 93k.