Vibration when coasting and/or slowing down

[DocBar]

A friend of mine has an '06 6.0 that has a pretty strong vibration whenever he is coasting or slowing down. If he gives it some throttle, it goes away.
It's a stock truck with a Superchip in it.

Any ideas?

 

[strokedoutinternational]

Does it feel like a driveline vibration like if a u joints bad or driveshaft out of balance.

From your mothers room Trebek

 

[DocBar]

Does it feel like a driveline vibration like if a u joints bad or driveshaft out of balance.

From your mothers room Trebek

The guy says it feels like wheel hop to him. I asked him to check his driveshaft, u-joints and carrier bearing, but he says since he doesn't hear a clunk when he changes gears, he doesn't think it's u-joints. I can't even get him to crawl underneath and check, so I think he just needs to put it in the shop and pay someone else to check it.

 

[strokedoutinternational]

I'm not a know it all by any means but a clunk or vibration could be caused by a u-joint

From your mothers room Trebek