ok well my truck clunks when going from forward to reverse and has a slight vibration at hwy speeds so i thought id check the u joints... one looks ok the other could do but is starting to go so im going to replace em both. my other issue is that when turning at low speed like just above an idle i gear a sound similar to a grinding/squeak. my friend determined its comming from the back end of the truck. so while checking the ujoints i noticed play in the rear end.... i dont know how much there should be so i took a video.

truck is in neutral with wheels blocked in the video.
also noticed a bit of play vertically abs side to side in the yoke on the tcase. im guessing there should be some movement there?
‪Is this ok?‬‏ - YouTube

 

mine has play like that too, but yours seems a little excessive from the video. if its making noise from the rear while turning, that's usually a sign of a bad rear end. what kind of truck is it? im assuming its a 95 150. its most likely an open rear which isn't that hard to fix as long as you only need spider gears. i would definitely replace the u joints and go from there.

 

95 f150 4x4 3.55ls
its kind of a creeking sound... i cant really describe it...
will tightening the nut on the end of the flange when driveshaft is removed tighten it up at all?

 

i dont think so, but somebody else will have to chime in on that one

 

The pinion nut on the axle sets the preload on the pinion bearings. Do not try to tighten this, it will only cause more problems. You should take off the differential cover and have a look inside. The axle in my truck has about that much play and I found that the spider gear thrust washers were about destroyed and the lock bolt for the cross-pin in the differential had broken in two.