Hoping someone can help! I have a 1997 F150 Extended cab 4x2 that developed a wheel hop (like a tire balance problem) and vibration. Occurs at higher speeds in the 60+ mph range. Have had the truck in several times for suspension checks, front end alignment, new schocks, universal joints, brand new Michelin XLTs (balanced and rebalanced) and problem persists. No one can seem to isolate the problem that is causing this. Anyone seen anything similar?

 

Bad shocks, u-joints, or an unbalanced or bent driveshaft.

 

ball joints, check for a slightly bent rim or out of ballence, possibly a parking brake sticking.

 

might want to check the tire for a ply seperation.. kinda sounds like that would be it... does it go thum thump thump as u drive fast the thump gets faster? if so its usually a tire rim issue. we see alot of ply seps at work and i didnt even kno what they were til i started working there ha

 

Could a broken or weak transmission mount cause this type problem?? I got under the vehicle and with a large screwdriver was able to get a good amount of up and down movement in the transmission.

 

definetly need to fix that, but most of the time a tranny mount you will hear it clunk when it shifts, b.c of the torque. But during a normal cruising speed, holding one gear, you shouldnt be able to tell.
-Patrick

 

Where does this problem happen? If on a concrete highway/interstate it can be due to the length of the cement sections. Sometimes they are just about the same length as the trucks wheelbase and will cause a harmonic vibration that seems like a balance problem. Just my experiences.