Severe, intermittent vibration at highway speeds

[turkish]

At 70mph I began noticing a slight (but noticeable) vibration. It remained constant for a few miles and then suddenly got so bad that I had to pull over. I've been in vehicles that rode poorly on the highway, but this thing would've shaken apart had I not at least slowed down. I did not turn the truck off, just put in park. Idle was normal. A quick inspection of tires showed nothing out of the ordinary, so I resumed my trip. I went another 6-8 miles to my destination with the truck behaving 100% normally. On the return trip, the vibration returned, but less severely. This time, while the vibration was ongoing, I had to slow from 70 for a stoplight. I noticed this time that the truck shook worse during braking, as if a rotor was badly warped. I stopped at this stoplight. After regaining highway speed, I'm not sure that the vibration returned. If it did, it was pretty minor.

 

Truck is a stock 2010 5.3 ext cab, Z71 with original tires and 40k miles.

 

Does this sound like a tire issue? At one point during the problem, I put shifter in manual and downshifted to 5 -- I noticed no change in the vibration at all. This tends to make me dismiss engine/tranny. However, can something intermittent like this be tires or joints? Desperate for some help. The truck isn't driveable if this continues, and I have zero faith in my dealership.

[SILVERADOSC540]

Could be a tire, or perhaps you slung off a wheel weight. I would jack up the front end(assuming it was in the wheel and not your a$$ where you felt the vibration) and try turning each front wheel left to right. If there is any play in one or both I'd have it checked out before hitting the highway. If not, try a balance and rotation.

[turkish]

My tire guy is guessing front end issues. Dealer seems to suspect drivetrain (mentioned maybe bad gas). I did fill up right before this started. Neither of them could look at it this afternoon, of course.

[GMCustomerService]

Keep me posted on your progress turkish. Contact me if you need additional assistance. Thank you.

 

Tricia, GM Customer Service.

[crankman]

I am going to agree with the tire weight slung, might look real close sometimes you can see where the weight was they tend to leave a little mark on your rims.