Rotated & balanced tires. new driveshaft & center carrier bearing u-joints new shocks front & rear replaced rear axle bearings and seals new left rear rotor parking brake shoes new disc brake pads all of this looking for vibration 45mph on in rear also had driveshaft balanced,what esle could itbe

Is there any evidenced or knowledge of this vehicle having been in an accident? It's possible that a half shaft is bent (although seemingly unlikely) or maybe the carrier bearing for the driveshaft is bad.

If none of the parts you replaced made a difference, I'd be considering bearings. Is the shimmy felt mostly in the body of the vehicle or in the steering wheel? If mostly in the body, the issue is probably related to the rear axle. If the steering wheel shakes, the issue is likely related to the front axle.

Could be carrier bearing(s), worn gears, or bad driveshaft joints.

I'm guessing your you are referring to the drive shaft center support bearing. Remove u-joint 4 bolts at rear diff., then 2 bolts for center support. Slide driveshaft assembly out of trans. and lay on ground. On either side of the center support, make alignment marks on front and rear half of drive shafts with a crayon or tape (very important for re-assembly). Slide rear half off. Press out center support. Clean sleeve with emery cloth or 400 grit sand paper. Press on new center support, lube splines and reconnect drive shaft halves making sure alignment marks meet. Install assembly and torque bolts.

Rotors and brake calipers.

1) Flat level surface, chock the front tires.

2) Jack the rear up just until the tires clear.
USE jack stands. (DO NOT EVER just depend on a jack)

3) Remove the rear bolts holding the rear U-joint in.
Carefully use a tool to pry one of the U-joint cups, until the U-joint comes loose. DO NOT drop the cups off. Keep one hand wrapped around the cups as you pry the U-joint loose.

When U-joint is removed, suggest use black plastic electrical tape, and tape across the two cups, so they do not drop off.

[GOOD time to see if they are dry, and the U-joint is in good condition. DO NOT loose needle bearings ]

4) Remove the bolts that hold the Carrier Bearing Support to frame.
(Put the nuts back on a few threads of the bolts, after putting them back through the holes, in the Carrier Bearing Support strap. This way you won\'t lose them)

Lay the Support strap, and rubber aside.

5) Slide the driveshaft out of the back of the tranny. (Transmission)
It would be a real good idea to go to an auto parts store first, and rent a plug tool for the back of the tranny, once you remove the driveshaft. Keeps the tranny fluid from leaking out. Manual or automatic. (It is plastic, and a cheap rental)

The rear half-driveshaft slips out of the front one.
BEFORE removing make a mark on the front half-driveshaft, and a matching mark on the rear half-driveshaft. The driveshaft is a Balanced unit. Should be put back together the same way, it was taken apart.

Take the driveshaft with the carrier bearing on it to a shop, so they can press the old one off, and the new one on.

Reverse your steps.

(Owner of 1994 GMC Sonoma 2-wheel drive, extended cab. Civilian mechanic on Army base. Work on ALL wheeled vehicles, and track up to, but not including, Abrams M1A2 tank )

Regards,
joecoolvette

My two guesses, based on what you have written, are tire balance (or tires, period) or a wheel bearing.

Hello, I see you may a lot of changes and replaced a lot of parts. We leased an Explorer the same Year as yours. In our case there was a slight noise as well as vibration. The problem was the Front Hub bearings, They were bad at 18000 miles.

There are a few things I want to suggest. The spinning of the wheels on the lift will not load the bearings. A Dyno table can get everything turning with a load on it. As your vehicle is a 4x4, most Dyno's were 2 wheelers. You would have to call to find one for a 4x4.

Next, if the new Hubs do not help, have a look at the rotors. They are also balanced. You can spin balance the Wheel and rotor as a unit with a floor motor. It's not the best way to Balance because tire rotation or even shifting the Wheel on the lugs will UNbalance it. But this method CAN pinpoint a problem if a Balanced tire does not spin true when bolted to the vehicle. You will know the Rotor is off-balance and which axle is causing the problem.

Would be interested to see a Post of what you found.

could have bent rim,,even thow,,balance was done,,depends on how mush weight was used to balance?? rotate tires from frt to rear,,see if problem still exits,,ck bearing play,,hoped it helped

check cab to chasis mounting rubbers.
can remove one or two bolts and see if change in vibration

cardan centering bearing
point bolts needed to be removed that connects D.S.to transfercase