Bouncing Rear End

To much Air Pressure in your tires Possibly. If you have 80 PSI in them and your truck isn't loaded down in back, then your going to get a bouncy ride. Don't air up the tires to what the MAX AIR PRESSURE on the tire says. Usually it'll say on the door tag what the front and rear Air pressure should be at. But even they you may want to drop it a bit. Say

Possible that one of the belts in the tire has seperated. _Carefully_ and slowly rub your hand around the outside of the tire to see if there are any buldges. If the problem has been there for awhile there might be some broken bands of metal sticking out that are sharp.

Too much air. Check tire pressure there may be a range from 40 to 80 if they are "D" rated tires. Lower pressure when no load will give better ride.

Tire out of balance: Rebalance tire

Shocks: Shocks can be worn. You will usually see cupping on the edges of the tire if the shocks are worn.

The tire itself: steel belts on the inside could be slipping

Sarge

Thank you for your inputs. I'll try the tire pressure thing, makes the most sense. Then the balance, then the shocks. The tires themselves are fairly new.

I've had situations where the new tires were simply "out of round" and could not be balanced to compensate. The good tire shop can confirm if this is the case.