High Speed vibration, not tire related

My 2004 Eddie Bauer Explorer V6 with 110K miles has a vibration problem that I need the forum's expert input on. First I assure you that the vibration IS NOT FROM TIRE BALANCE! How do I know? Multiple balancing, rotation, alignment visits did not help and now on my 2nd new set of tires with the same issue.

I have replaced : the upper control arms and ball joints on the front.
New shocks/struts (whatever they are) all around.
inspected, tugged and kicked the wheels to check for bad wheel bearings and no loose play whatsoever
gotten under the vehicle multiple times to inspect tie rod ends, axle boots and shafts, u-joint, any loose bolts or dripping oil - all are fine to my eye

The symptoms as I can describe in no particular priority:
1) at about 50 mph the back seat shakes such that the seat belt hanging from the roof will begin to bang against it. At the same time you can feel it in your butt while in the driver's seat.
2) The steering wheel vibrates minimally going straight, but on a curve while at speed the vibration in both the car and wheel worsen.
3) Sometimes the shaking is not so bad, but still present. Cant seem to correspond the "good" days with any factor
4) Listening while in the car the sound that I hear is very hard to describe. It sounds to me as though something is vibrating up and down very fast with a la-da-ba-la-da-ba kinda thing going on. Not very loud and I might even be hearing something that is not there?!?!?
5) and combined with the above sound I have the sensation that the whole tire and wheel assemblies in the rear are vibrating up and down along with the above noise - like an out-of-round tire would create.
6) and finally when making a maximum turn with the wheel while in reverse, there is a noticeable "clicking" sound from the front suspension - occurs about 1 click per every 2 secs or so??

My wife jokes that riding in my Explorer is kinda like using one of those weight loss belts from the 60's. You know the ones that went around your waist and supposedly shook the fat off - Except I ain't losing any weight!

Any input would be tremendously appreciated. Thanks!

HatchMan42

Sometimes the bearings can be bad without exhibiting the "moving wheel" syndrome.

taking a guess from here it could be a couple of things,
Most common are the Rear Wheel bearings they have a history of going bad, although they usually make noise as they go bad, maybe they are shot beyond noise and since its IRS those vibrations can travel and make it hard to diagnose.

Then least common but not unheard of are the:
Rear Diff Bearings, the seals sometimes leak where the half shaft go into the diff bearings, then inside the diff itself.
CV joints and drive shafts could also be a problem.
Bent drive shaft is a chance too.

There are about 6 joints back there all of which can cause vibrations, you might get lucky and find some play in one of the joints, if you grab it with your hand and can wiggle it at all up/down side/side also where the shaft goes into the CV joint itself look for rotational slack. The whole shaft may rotate a little 0-5mm but it should not be in the joint.

If you don't have a means of checking it yourself, maybe a Gear/Trans shop might have better experience at finding the problem.

There is a Ford TSB out for high speed driveline vibration. That might be what you have going on. It's TSB 05-16-4 and you can see it here: http://www.fcsdchemicalsandlubricants.com/supplier/tsb/05164.pdf

In Tucson where I live there are a couple of shops that specialize in driveline balancing. Maybe you can find a place like that in Dallas and have them take a look. Should be easy for someone with an analyzer to spot. Good luck.

i have a 04 and sorta have the same symtoms.

thing is though it feels like it is vibrating up front.

i swapped the spare on all 4 corners and that didnt help.



you figure anything out?

i have extended warrenty still and i am going to take it in here soon. i will post up details.

good luck

Rear Diff?

I have an 02 that I put a rear end out of an 04 into. The 02 rear had a bad whine in it and now I have the shake from 50 mph to 65 mph. I have come to find out that 04-05 rears have this problem and 02-03 rears whine and Ford does not have a good answer. I am told to get used to it but I am still looking for a better answer.