I replaced the U joints on my front drive shaft today and when I put it back up it now wobbles like crazy.

Any thoughts on the problem? It was fine before the new U joints.

 

So I attempted to use 4x4 again today to get out of my driveway since there was about 6 or 7" of snow in it but when backing up I heard like a loud poping/grinding noise, any thoughts?

 

Sounds like when you put the u-joints in either not seated in properly or misaligned. Check to make sure you didn't bend the driveshaft or the flange. Best bet is to pull the shaft out again inspect both ends. May have yo knock the u joints out again and make sure none of the needle bearings fell in the cap