shimmy above 60mph

[hunterguy86]

I have an 86 k5. Everything is stock. When I go above 55-60 mph everything shakes. I've looked at the tires and they look good. I just bought them in march.
All the wheel weights are still in place as well. What should I be checking for. Its really annoying when drivin on the highway.

By the way I'm runnin 31x10.50x15 kelly AT's

 

[readymix]

Check the u-joints

 

[guido666]

I know I start to get a shimmy when the steering stabilizer is going bad. Might be worth checking.

Could be alignment also.

 

[hunterguy86]

Check the u-joints

Could this possibly be it? I do notice a bit of a whine when I left off the gas. Maybe the 2 are related. What should I look for when checkin the ujoints

 

[readymix]

Check to see if there is any slop in the joint, Also verify that there is grease in them.

 

[guido666]

Could this possibly be it? I do notice a bit of a whine when I left off the gas. Maybe the 2 are related. What should I look for when checkin the ujoints

See if they are obviously broken or mangled. Then see if there is any slop in them (put the transfer case in gear, lock the hubs, jack up the front axle, and wiggle the tire forward and back and see if there is slop between the two halves of the shaft).

 

[hunterguy86]

I'm pretty sure the alignment is good. It dont pull in any direction so that should be ok

 

[PsychoticDeadGuy]

mine does this also but only between 60-74 and at 75 it completely stops and i can cruize at that speed fine, untill i see a CHP.

 

[Leper]

Alignment will never cause a vibration. Put the truck in neutral and see if the shaking stops.

 

[guido666]

Alignment will never cause a vibration. Put the truck in neutral and see if the shaking stops.

It will if you get it so out of alignment that there is a toe in/out condition. Remember my thread about that you replied to? It would hop when moving slow, then it was unnoticable until you hit about 45 and then the harmonics were just right. I fixed the toe-in and it didn't do it anymore (it was the only thing I changed).

 

[Leper]

It will if you get it so out of alignment that there is a toe in/out condition. Remember my thread about that you replied to? It would hop when moving slow, then it was unnoticable until you hit about 45 and then the harmonics were just right. I fixed the toe-in and it didn't do it anymore (it was the only thing I changed).

Yes, I did not take into account a tire that was visibly pointing in a different direction than the other.

 

[guido666]

I wasn't trying to be rude, and my tires were nowhere near VISIBLY toed in. They were off by about 1/4-5/16" together in the front vs. the rear of the tires' measurment. It didn't take a lot to make a huge difference. That's why I suggested it.

Oh, I sent your console by the way.