Hi all
i have a 2006 Supercrew with a vibration I have been chasing for a while
At low speed (10-40 kph) the rear of the truck literally bounces up and down.
at freeway speeds the whole truck vibrates.
Got my old wheels rebalanced, issue didn’t change
Got a different set of used wheels, got them balanced right away, and bounce is still there
Just replaced the U joints today, no change
checked the pinion angles and both are 3-4 deg
Rear brakes are only 2 months old

I am at a loss here, please any advice!
Thanks

 

have you tried changing fluid in the rear differential?

 

No I have not, you think that could be the issue?

 

Possibly. It's cheap enough enough to try

 

What about tires ?

 

Yep. Didn't think about that. Tires could have broken belts

 

Or out of round... no amount of balancing will correct an egg. I've even seen issues with tires mounted improperly, with the beach not fully seated against the rim, which creates an out-of-round situation.

Beyond that, I'd be looking at frozen springs, seized u-joints, broken carrier bearing support, balance/trueness of the driveshafts, etc. Being a supercrew, methinks it has a carrier bearing, in which case both driveshafts should be balanced against each other and re-installed with their correct respective clocking as when pulled apart, or vibration may result.

 

he said he replaced the u joints already and it didn't change. i would think that if the wheel or tire either one were damaged, the vibration and/or bouncing would be felt at ALL speeds. which is leaning me towards a drivetrain/suspention issue. a damaged tire or wheel can't fix itself, meaning it won't go away on it's own

 

I know he did, but that’s still where I’d first look. Were the joints installed correctly centered to keep the shafts from whipping around? Were all 3 joints replaced? Were the shafts reinstalled correctly clocked to one another to preserve their dual balancing? These are questions whose answers we don’t yet know.

Mechanical objects don’t fix themselves, but different people have different tolerances for observation. I had a potential lawssuit against Fiat-Chrysler for something along those lines.

 

Bring the truck to the speed of vibration and then put the truck in neutral and see if the vibration goes away. If it does look at drivetrain. If it doesn't look at tires.