still have a rough ride, truck feels like the rear is bouncing at hwy speeds (65-75mph)

it's got new shocks and tires, drive shaft was done over back in june, front ball joints were replaced about 2 yrs ago

funny thing is the truck runs good on aspalt but bounce's like hell on concrete roads

if i hit a dip in the road it smooths out and starts bouncing again

i did notice a loose clamp on the springs, so i was going to try them next
any other suggestins to try

 

possibly to much air in the tires.

 

I'm not sure what load range tire you have, but I have load range E's and the ride is stiffer. As far as concrete highways, they never ride good, regardless if you're in a lexus or pulpwood truck. Like was already mentioned, check your tire pressure.