Excessive vibration

[BPowers]

The other day I noticed that around 50+ MPH the truck started to have excesive vibration when on the gas pedal. When I would let off the gas pedal vibration seems to go away. Listed below are possible options in the maintanance manual. Any ideas on where would be the best place to start or anyone have any other ideas? Also at 50+ mph the exhaust has a different sound as well. This also just started the other day when things started to vabrate. It sounds like something could be plugged up. Exhaust now sounds muffled and lower than usual. Anyone have any ideas??#@$%!

1. Loose or broken engine mounts.



2. Damaged fan or improperly

operating accessories.



3. Improperly operating vibration

damper



4. Improperly operating viscous fan

drive.



5. Worn or damaged generator

bearing.



6. Flywheel housing misaligned. 6. Check/correct flywheel alignment.



7. Loose or broken power

component.



8. Worn or unbalanced driveline

components.

 

[jelag]

You don't say how many miles on this truck, but from our experience the key item that seems to give everyone grief is u-joints and the ability to test them... . we have several of these trucks and we've had problems with u-joints to the point where we pull them down and grease them... .

We've also found that they are very hard to diagnosis without a tear down, or just wait until they get really loose... .

As they get dry and start to turn to dust (needle bearings) they don't give much of a problem unless your under a load... .

 

[RKershner]

Had the same problem last week it was the rear u-joint. also posted a thread on this last week "vibration". Hope this helps.

 

[BPowers]

My truck has 102,000 miles on it. I do have to replace u joints. The two up front and the rear one as well. I thought it might have been this as well. Wasn't sure though if it could have been something with the engine.