I have a 2010 ford f-150 stx extend cap 4.6L. Normally between 50 to 55mph the truck bounces. 60 to 75mph the truck is fine with no vibration. Once I get over 75 mph the bouncing will start again. I have tried everything. The tires have been balance twice. I have placed the truck in neutral around 55mph and it still bounces as it slows down. All the weighs are on the drive shaft. Could it be a busted belt in a tire or is it a drive shaft issue? I have read a few things about drive shaft issues? Also, the temperature outside does affect the bounce/vibration. There is less bounce when cold but more bounce when warm. Thanks

 

Most likely it's a tire causing the problem. Rotate the tires front to rear and see if it moves the vibration.

It could be something like a bad u-joint. Usually, I think a bad u-joint would change the vibration based on throttle position.

I've seen sticking brake calipers that caused a bad vibration too.

How many miles are on the truck?

 

The truck has 62,000 miles. I think the vibration moved when the tires were rotated.

 

When the vibration comes and goes at different speeds like that it is almost always wheel balance.

Any chance that someone added that liquid flat repair to one or more of your tires (ie. Tire Slime)?

 

I would go to a good tire shop and get the tires carefully inspected and road force balanced. They may need to be "clocked" on the wheels, one or more may be out of round, possibly broken belts. You may also have a bent wheel.

 

I am having the same issue with my 2012 Ford F150 stx

The shaking is exactly at 55-60 and above speed it stops.

I have changed the drive shaft with all new U joints, brand new tires (all 4) with alignment and tire rotation. The issue still there . Any ideas ?

 

The first thing I'd do is look at the backs of the rim-hub area. Make sure it is clean and there is no corrosion in the center of the hub.

I'd had scenarios where the inner hub of an alloy wheel had corrosion, and it would not seat correctly on the hub causing this same exact scenario.

If in doubt, get a wire brush on a drill and clean it up. To the naked eye, everything looked OK. But when mounted, even to the correct torque specs, it wasn't truly sitting on the hub.

Just a suggestion...

 

Has your truck been lifted?

 

Yes, I check the suspension and seems fine. Just bought this truck but I can't figure out whats causing this.

 

A lift aggravates any imbalance anywhere.

 

any suggestions? things to check

 

If the driveshaft is one piece, the ujoint angles at both ends have to be the same because if there is any angle, the shaft will speed up and slow down every revolution. But if the rear ujoint angle is the same as the front, it cancels out. the shaft will still be speeding up and slowing down but the diff will turn at the same speed as the trans tail shaft. If the angles are not the same there will be a driveshaft vibration. Here is a demonstration.

 

I have a two piece drive shaft. Would this be an issue ? The drive shaft ends are not in any angles. They are pretty straight

 

I just googled your drive shaft and the photos I saw showed a u-joint in the front and rear of the rear part of the drive shaft. So, the same principle would apply to your drive shaft. The u-joint angles may not be the same and if they are not, it would cause a vibration.

 

Check the caster on the alignment and go with Bilsteins