Slow Pulsing shimmy at 70 mph

clanofwolves

clanofwolves

New member
My 2001 has a slow pulsing shimmy that occurs only above 60 mph and is best described as gradually increasing to an uncomfortable steering wheel shake for about a second, then diminishing over a second or two, as in waves. It is consistent at highway speeds and 'pulses' at about 4 second intervals.

Here's what I've done:
Replaced steering rack bushings
Full four wheel alignment
New set of balanced Michelin LTX MS2 tires

The shocks and struts don't have a great deal of play and seems to fall within the rule of thumb 'bumper push down and release' test. Although I haven't replaced the front wheel bearings, they don't make the familiar 'bearing gone bad' sound, but I don't know how else to test them.

Any ideas fellow owners???

Thanks in advance for any help!
 
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Cheking the shafts....?

Ex-ToyTech said:
If it's a 2wd I would check the u-joints.

Tim
Click to expand...

Thanks so much for your advice!

What is the best way to check them on this truck?

Also, the drive-shaft seems as solid and immovable as possible in all directions when I have attempted to move it by hand with the truck in park; when it is in drive, the end attached to the transmission has a 1mm movement with a slight click...not sure if this is within spec or not. The rear u-joint has no play or sound.

As a possible related question? ...there is slight movement (1/4" max at edge of tire) when I attempt to turn a hanging wheel (as the steering would do) when the entire front of the truck is suspended, but I'm not sure if a bit of play is normal.

Thanks!

David
 
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Sorry for the delay in answering- been out of town.
It would be best to remove the driveshaft. You probably have a "tight" u-joint. After you remove the shaft, move the joint in all directions of pivot. You will probably find it binding in one or two directions.
As for the free play in the steering, check the tie rods and also the rack ends. And make sure the rack mounting bolts are tight since the bushings were replaced.

Tim
 
sorry but if you have a steering wheel shake its not the u-joints... check you lower ball joints for play and your outer and inner tie-rods for play, you could also have worn out bushings on your lower control arms, but typically with LCA bushings you will get a pull to one side or the other during breaking
 
steering wheel shake from u-joints in a 2wd? someone please help me here with this!!??!! :help:, im not fallowing how this is correlated, i have felt bad u-joints, and or improper u-joint angle vibrations, but i never got a steering wheel shake or vibration from them. im a little confused here
 
I'm 2wd and lifted... I also have this vibration... And my u joints were junk and have been replaced along with the driveshaft rebalanced... In my case I need a driveshaft spacer, so the front section has more spline contact

In your case I'd check the front end components like mentioned by others... My vibes do not affect the steering wheel it is high frequency on the floor board
 
Skidmarcx said:
I'm 2wd and lifted... I also have this vibration... And my u joints were junk and have been replaced along with the driveshaft rebalanced... In my case I need a driveshaft spacer, so the front section has more spline contact

In your case I'd check the front end components like mentioned by others... My vibes do not affect the steering wheel it is high frequency on the floor board
Click to expand...

hence in my build thread "custom drive shaft"...well kinda custom, it's just not the one thats supposed to be on my rig haha
 
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I actually have the same issue on my 2002 4Runner SR5, except mine is 4wheel drive. I have yet been able to fix it, and have no idea what is causing it. If you figure it out let me know!!!
 
Ex-ToyTech said:
Not saying they are definitely the problem but also speaking from almost 28 yrs. as a dealer tech.

Tim
Click to expand...

I have felt the drive line shake from u joints... But its never been a shake that comes through the steering wheel... That's what confuses me about this and everyones diagnosis...:confused:
 
Thorgan112 said:
I actually have the same issue on my 2002 4Runner SR5, except mine is 4wheel drive. I have yet been able to fix it, and have no idea what is causing it. If you figure it out let me know!!!
Click to expand...


Same thing on my 98 LTD 4x4 . Seems to be quite common .

I will drive to town ( 30 miles or so ) and it will do it intermittently . Do my thing and then head back home and its gone . WTF would make warming things up , temporarily correct the issue ?
 
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I have a vibration that starts around 60 mph and I haven't confirmed the source but the other day I was underneath grabbing the rear drive shaft checking for looseness and the output from the transfer case was wobbly. I haven't been able to tighten it yet but I'm guessing this is the issue. Not sure if it is a bearing or what but you should definitely check to see if that is causing the problem. Just give the drive shaft a wiggle near the transfer case and see if it is moving a noticeable amount. My rear does but my front does not so I'm assuming it's not right. If it's not tight it could definitely cause vibrations. Check it out and good luck!
 
Dropped my rear driveshaft today and tightened the staked nut coming from the transfer case and the looseness is gone. Still not sure if it took care of the vibration because I decided to paint the driveshaft while it was out but it definitely seems promising.
 
blonde1boarder said:
Dropped my rear driveshaft today and tightened the staked nut coming from the transfer case and the looseness is gone. Still not sure if it took care of the vibration because I decided to paint the driveshaft while it was out but it definitely seems promising.
Click to expand...

Thanks for the info. man , I'm going to crawl under mine in the morning and check that out . Report back if you found any improvements .
 
the kid said:
I have felt the drive line shake from u joints... But its never been a shake that comes through the steering wheel... That's what confuses me about this and everyones diagnosis...:confused:
Click to expand...

It usually can be felt in the steering wheel when the joint(s) have gotten so "tight" they won't hardly move. If you have worked on many 'yotas, it's kind of like a Sequoia rear axle bearing. You would swear the noise is coming from the front wheel bearing. DAMHIK. :crazy:

Tim
 
All this sounds similar to what my 97 t4r is doing. It's 5 speed and 4x4. At speed if I'm cruising at say 65 theres a vibration in the seat and a little in the steering. If I back off the accelerator or ease into it and speed up the vibrations go away. But, if i just set the cruise its a constant vibration/humming in the cab.
I guess I'll crawl underneath and see what I can find loose in the drive line.

Any other thoughts would be appreciated.
 
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