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.

that clunk you hear is "normal" for chevy trucks. it comes from the factory like that with a certain amount of lash. my 04 1500 has been to the dealer twice on that issue. and when the techs checked the joints. they checked out fine. (what they call it)

you could jack it up in the rear..and have somebody get it up to 50 mph.... it probably idles at 30mph..lol anyway ou might be able to tell this way

could be a tire issue.