when i take my foot off the brake and just coast. my truck bounce's until i hit 5 mph. it seems like it's coming from the rear. when i went to inspect my truck at the state inspection station. they put it on a dyno and i saw it bounce. has this ever happen to anyone. i bought the truck 2 months ago and it's done it from day one. appreciate any help. my user name is the truck i have.

Paul

 

F350,
Two piece driveshafts can cause this sort of symptom. They must be "in phase". Simply line up your yokes. A worn pinion gear in the rearend could cause the same problem but howling/grinding and oil leaking are also to be expected sypmtoms.
My Way is the Highway,
KingFisher

 

I had this happen once due to worn out shocks.

 

rims bent? tires out of round?I was running some 38"bias ply tires and had the same thing.

 

It couldpossibly also be u-joints. You might check those also .

Don

 

well the truck has fairly new shocks, tires and rims. so im gonna check out the drive shaft this weekend. thanks for all the reply's i'll let you know what happens with it.

Paul

 

look at the brake drums for out of round. it is not that uncommon for a loaded truck to get the drums real hot and then you stop and set the parking brake and it flexes them out of round. it is not as common on light trucks but you should have seen the ones on the back of my F250! hawkrod