Acting like tires are un-balanced, but there not, and ideas?

[97-5spd-powerstroke]

so I took my truck to ole les schwab yesterday cause it seemed like the tires needed balanced cause it was vibrating like when your tires are out of balance but as soon as I pulled out of the parking lot it was still doing it and didn't change at all, I notice it most at 35mph, and ideas as to what this could be?

[melmount]

failing injector? A cct test when the motor is cold will confirm one way or the other.

[retmotor]

Les Schwab?? Personal experience on a car we owned taught me they don't know what a hub-centric wheel is, maybe they don't know how to balance wheels and tires. (OK, maybe I'm being a bit harsh, I just wouldn't totally trust 'em is all...)

[retmotor]

Hey, what tires you running and how old are they? Tread separation could be the culprit and it's not always visible. Les Schwab should have caught that if that was the case, but again...

[97-5spd-powerstroke]

Originally Posted by melmount

failing injector? A cct test when the motor is cold will confirm one way or the other.

cct test? whats that?

and I am runnin toyo a/ts that are kinda bald but have prolly enough tread to make it threw the winter, I've been told that they could be separating so I'm not sure and the guys at schwabs weren't really paying attention to my tires when they did it, they were too busy talking so I'm not sure

[Chop]

Check your U joints and carrier bearing.Could be drive shaft vibration or a U joint going south

[jimmm]

where can you feel the shake? if you can feel it in the steering wheel, its most likely the front tires, in the seat, its your rear.Balance will usually get worse at faster speeds. Out of round, or bent wheel will get better.U-joints, carrier bearing is a good place to look too. You might try jacking one rear wheel up and running it at speed to see if its in the drive train, tho dont try this if you got a limited slip rear end. Check for bent drive shaft in case the last nose picker that jacked your truck up used the drive shaft to lift it, ( seen that done before). If tires were rebalnced did they take the old weights off or just add more to it? Tire separation usually doesnt shake but feels more like a slither, and can be seen or felt a lot of the time if you look close, tho it should have showed up on the balancer.You can rotate tires to see if it changes.That would tell ya its in the wheels or tires.Since its at lower speeds, I dont think its a balance issue.Balance typically shows up above 45mph.I'm betting something wore out, or bent.

[superduty4x4]

U joint, probably the one on the rear diff.

[97-5spd-powerstroke]

Ok I'll check out that stuff at work tomorrow, thanks guys