Replaced the 2 u joints on 2005 gmc yukan 2 wheeldrive and auto started vibaration teriable ?

If you have only changed the drive shaft universals then its obvious that something is wrong ,so firstly check that the shafts are not marked to align up with something ,then if need be remove the shafts and check for alignment because if you have used a big hammer in any way detrimental you may have damaged the shafts and bent one or both ,also makes sure the wheels are fitted correctly and their isnt rust or mud behind them ,so jack vehicle up and spin each wheel and look for anything out of the ordinary ,also the two shafts you changed the joints in make sure that when you spin the wheel by hand they look a nice smooth turn ,but i have a funny feeling you have bent the shafts by putting them in a vice and knocking the UJ s out as their is quite a art to this job and a bent shaft is easy to do ,trust me i know because i have bent a few by heavy handling as well ,iam no angel and can get carried away with big hammer as well as anyone