temporary vibration--how identify?

[Drewmcg]

On a fifty mile trip on the expressway last night, I heard/felt a new vibration. Very annoying. It almost felt like it was coming from the roof behind the drive seats (but it wasn't). It persisted for 20 miles or so, and seem to fluctuate (and even stop for a split second) going over bumps, with the suspension motion. It eventually went away.

Thoughts on the source/how to diagnose the problem?

 

[firefly1246]

I would begin by doing your best to determine where it is coming from. After that focus in that area. I would check if anything is loose or wobbly.

Vibrations can come from tons of stuff:
Suspension component broken/worn out, ball joint bushing, etc
Cv axles are shot ( would be loose if you wiggle them)
Brake rotors (usually only during braking)
Items on the roof are loose
Driveline/driveshaft bent or bad u joints.


Sorry I am not more specific

-Scott

 

[Drewmcg]

Thanks. Suspension is tight and crossbars had been removed from roof. No vibrartions on a recent 3,500 mile trip. Tires are old with very good tread--but if they were a cause I'd think it would be consistent at a given speed.

I'm starting to think its a rear wheel bearing--which apparently are a known issue on these trucks. But I wish I could be sure, since that job looks like a PITA/expense, and I'm not confident I even know which side its coming from . . . .

 

[firefly1246]

Usually when I have had wheel bearings fail they make a high pitch howling sound. The sound follows your speed.

 

[Drewmcg]

good to know