Okay LOL I am about to rip my hair out over this frustrating issue. Between 60-70MPH my truck shakes, it shakes beyond 70 but it is much less severe. I can make it severe by braking between 60-70MPH. It feels like the truck is rocking side to side almost, but its originating from the back.

Here is what I've done:
* Rebuilt the front end besides the swaybar bushings and links 30k ago.
* New pitman arm and steering box about 12 months ago.
* Two different pairs of U-Joints, last set being nice Moogs.
* New rear shocks.
* New tires
* Different tires/rims from a car that doesn't shake.
* Turned drums
* Rebuilt axles from another 4Runner.
* Custom/new driveshaft built from a Toyota Prerunner driveshaft.

NO play in ball joints or tie rod ends.


I drove it without the rear driveshaft this morning and still felt it shake in the rear. How can this be? Is my diff toast? What else am I missing I've been chasing this issue for two years.

 

bent rear axle? bad axle bearing? Bent rim, tire out of balance...
Did you replace the tie-rod ends and pitman arm in the front? double check for play. Also look at your tires, they may tell you where the problem is coming from.

 

I replaced and rebuilt my axles with new bearings. Exact same issue. I checked it a feeler gauge and spun them.
As I said, I checked with rims and tires from another 4runner that didn't shake.

And, as I said, I got new tires.

EDIT:
new pitman arm about 12 months ago, and there is no play in the tie rod ends.

 

warped brake drums

 

I just had them checked and turned. Thanks for reminding me

 

Ok then, when it shakes is the steering wheel wobbling back and forth when you let go or do you feel the shaking through the seat?

 

No, I feel vibration in the steering wheel, but the front doesn't feel like its shaking or shimmying. I feel it mainly in the seat and in my calves.

I could try to rig something up like a seismograph if I have the time after I get the driveshaft balanced.

 

If your steering wheel shakes you have a vibration from the front end 95% of the time. maybe warped rotors. check for discolored patches on the rotors or have them turned or replaced. I generally go for replacement when the pain in the ass vs cost ratio is high.

 

I turned the rotors yesterday. Very smooth beforehand but I wanted to be sure. The steering wheel vibrates but doesn't shimmy.

 

I see in your signature "totaled and rebuilt" is this the rig you are referring to? if so I wouldn't be surprised you have a shimmy!

 

totaled and rebuilt 20 years ago. PO rode/drove it said it never shook when he had it.
It almost feels like the tires are out of balance but I ruled that out when I took it down the highway with good tires and rims. Mine should be fine since it did the same thing.

 

The last piece of advice I can think of for now is to jack up all 4 corners and block it very securely off the ground, put it in 4x4 and let the tires spin (start at an idle) looking for any signs of wobble like tires out of round, tread wobbling side to side, bent wheel flange or something like that. CV axles? maybe rotate your tires and see if your steering wheel shakes more/less?

 

Oh, wait, you mentioned brakes, so drive it and lightly apply the parking brake, see if you get vibration, that will eliminate the front brakes from the system.

 

Ah, I should've specified what a new front end was. I did front shocks, CV axles, and new bearings on the hubs. I will try that, but I was a bit nervous getting up to 70 in the garage.
I checked the wheel flange with a feeler gauge and the old axle on the passenger side was off by a hundreth of an inch. new ones seem to be true. Rotate as in tire-ship rotate? New tires. I'm talking MAYBE 300 miles max on these.

I will do that today though my e-brake isn't the best in the world, and I feel the shake just slowing down. When I'm accelerating or decelerating fast thats when its really noticeable.

 

akwheeler might have something there.
Do you have any info about the wreck it was in?
Maybe take it to a frame shop and check to see if it's straight.

 

It was T-boned I believe because the a pillar is welded in and the whole passenger side was resprayed. I will.

 

The cure for the shaking and vibration in my truck was the replacement of the factory steering stabilizer with an OME steering stabilizer, rear axle oil seals and the rear diff. pinion ring oil seal, and tightened the stake nut just a bit more than what it was, and now when i release the gas no more vibration and when i'm cruising on the freeway no more shaking.

So it fells really smooth now.

 

How hard was it to do your rear pinion oil seal? Mine has a slow leak. I might try tightening and restating that nut like you said too. Would you happen to have the p/n for the oil seal? If not, don't worry about it. Thanks!

The driveshaft guy took one look at my driveshaft and said he'd build me one for $100. So I'm going that route.

 

The seal part # is 90311-38047 and the write up i used is 4crawlers, and when putting the stake nut back on i just tightened it a 1/4 of a turn extra to prevent vibration when letting go of gas pedal. http://www.4crawler.com/4x4/CheapTri...eal/index.html

 

And when you say rebuild the drive shaft you mean replace the u-joints? the price sounds fair since i paid the machine shop $40 to replace both front and rear u-joints on mine about 5 years ago, and i paid about $25 each at the parts store for the u-joints.