pharrett

My 2009 F150 4.6 4x2 has an intermittent vibration that occurs during highway speed. I had an alignment done, I have brand new tires, and even picked up a new OEM wheel to replace a slightly warped one. This weekend I replaced the original U joints, thinking they might be worn and throwing off the balance of the drive shaft. I still can not get rid of the shimmy. It's not coming through the steering, and it's not constant. Feels like it may be coming from the rear end. It comes and goes sometimes when I let off the gas or add power and sometimes after braking. While replacing the U joints I didn't see anything visibly wrong with the drive shaft, so I don't think it's that, but I could be wrong. I do have a slightly warped rear disc rotor that causes constant shimmy when braking, but this feels more like a bad tire would.

Any suggestions? I don't know what else to look for at this point.


Thanks in advance for any help!

seniorFORDtech

i would 1st have the rotors machined and roadtest again Also look at your cooling fan clutch it may me frozen causing the vibration.... has this happened after your new tires have your tires road forced balanced not just balanced
road force balancing will show a tire that is not matched to the rim and if you have a bad belt or even a flat spot in a tire. regular tire balancing will not generaly show these conditions..

check your suspension tie rod ends and look at your ball joints... look at the driveshaft see if any there is any dents or weights missing from the driveshaft.

gone postal

Dittos on the balancing.

I had a set of tires on a previous truck that I had to take back to the dealer 3 times to get them to try and balance them then wound up bringing them to another shop, getting them balanced, and handing the original shop the bill.

Trapper

Put the truck up on jackstands, start it up and warm to normal temps, and then have somebody in the truck and put it in drive. Bring it up to hiway speeds where you are having the issues. Look for tires that are out of round, out of balance, and any wheel shimmy. Also watch the driveshaft for balance and make sure it isn't flexing in and out of the yoke. That will usually tell you what's wrong and you can do it yourself.

Ckale

I am noticing the same thing about my truck, its an 01 5.4 4x4, I just put on a 6" lift, new tires, and new rims. Had them mounted and balanced and everything. A common thing that i dont have is a steering stablizer, could that be it?

pharrett

As for the tires, I had the problem before I bought the new set. The new set does improve my ride definitely, but that and wheels aren't the problem. When i replaced the U joints this weekend, I could not see any damage or dents to the drive shaft or anywhere where there were missing weights. As for tie rod ends, would I not feel the shaking primarily in the steering? I had most of the front end replaced when i bought the truck a few years ago. I did have new shocks put on about six months ago. This is the last thing major I had done before I can say I truly noticed the problem of the whole truck shaking. I had always had a slight vibration due to a warped wheel, but this is more pronounced and the wheel has been replaced.

As I said, the vibration is not constant. It comes and goes. When gone, especially after the new tires, the ride is smooth as silk with no pulling to either side. I can let go of the wheel and she'll continue in a straight line.

I do have the warped rotor that I believe to be in the rear, but if that were the cause, wouldn't the shaking be constant, and not come and go?

Thanks for the suggestions.

LWood52

As to the warped rotor, I would think that the longer/farther you drive it the more likely the problem would arise as I would think that the pads/rotor would heat up after awhile due to friction/heat.

Does your vibration start on a cold truck or after its been on the road awhile?

Larry

pharrett

It shakes whether running cold or warmed.

Anything with the shocks? Could loose motor mounts cause this? I'm just throwing things out.

This is the only problem I have with my truck, and it has 230,000 miles on it.

LWood52

Could be the rotor being warped and after have been run for awhile,( weeks, months, whatever), it has worn/damaged a bearing which in turn could be an "intermitent" problem.

Larry

pharrett

One other thing I've noticed is that if it's running smooth and then I hit a rough patch of road, it starts shaking again.