crazy noise in 3rd & 4th gear?

hey guys I'm getting a crazy loud noise when I'm in 3rd at 30mph thru 4th gear at 50mph. does anyone who what this could be? yes the truck is lowered in the front and bagged in the rear if this helps..

i found out today since my truck is bagged and it hits on almost every bump the tech said the back of my tranny is broke where the shaft goes starts.... anyone one in socal that can help me please let me know thanks.

did you see it broken for yourself? it's quite possible because your truck is bagged/modified, but in most cases if things are done properly and every drivetrain part is still within workable tolerances and angles, then there shouldnt be a problem in most cases.

i was going to say U joint