Hey guys,

I would appreciate some help diagnosing my 4runner.

I have a 98 SR5 with P265/75/16 Michelins on it that are in good balance. I have road-forced these tires and checked runout on wheels and the whole wheel assembly checks out fine.

I am getting a pretty bad wobble at higher speeds like 60+. When I come across a slight breeze, a gust of wind, ANY unevenness in the road, or just regular I25 driving the truck will go into this unpredictable wobble where it sways side to side and it feels like the front and rear drivetrains are chasing each other back and forth. The problem does not occur when braking. The problem stops immediately when I let off the gas and allow it to slow down.

It has been doing this for a couple of years now. It started out only happening in big gusts of wind I found going through NM on a road trip and progressively got worse to the point that it does it every time I am on the interstate.

I dug up an old post that had a lot of similar ideas:
https://www.yotatech.com/forums/f2/cause-roll-sway-highway-speeds-118872/


This thread had a lot of good pointers but nothing specific. Basically it says anything in the suspension or body that has worn out bushings could be a culprit (sway bars and body mounts more common). I have not seen any bad bushings on my sway bars but my steering rack has had some play in it for the last 50 thousand miles.

 

steering wheel wobble or the whole truck shaking?

Steering rack bushings is my immediate guess for the first and U joint failing for the latter.

Alignment lately? Tie rod ends and ball joints and so on checked out fine?

 

I had those same tires on a 2001. I had the same problems you had. Here is what it took to make it a lot better:
1. New steering rack bushings
2. New sway bar and end link bushings
3. This is the biggest-- Remove the steering column and weld the two shafts together. This was the most helpful of everything I did, although all of the three helped a little.
There is a write up here somewhere about it. Here is is:

http://ttora.com/forum/showthread.php?t=161689

 

Ron,
The whole truck sways/shakes. I don't feel it in the steering wheel as much but it does have some play in it at all times. I never would have thought a u-joint would make the whole truck sway back and forth on the highway..? My u-joints look good in the back, the one off the tranny looks a little greasy but I can't see any play in it.

jreask,
Thanks. 1. It has the poly rack bushings I did a couple years ago. 2. end link bushings in the front could be changed but the rest are fine. 3. If you weld those shafts together can you still remove it and service it later?

 

No the U joints would not be causing wandering all over the road. I'd get it aligned and see what shows up there. Get the print out showing the before and after to see what is way out of spec.. Other than that my gut reaction is something sway bar related.

 

How are the tires wearing on front? Maybe check the caster/camber. What about the rear control arms?

 

I'm agreeing with him. My truck had one hell of a shimmy when i'd hit bumps, about 2-3 month's after I lifted it. I threw it back on the alignment rack, and found that my toe was way out, along with caster on the passenger side. The two combined to create a hell of a wobble in the front end. Brought the caster in closer to spec (+ or - a degree or so) and dialed in the toe, and haven't had a problem since.

 

Another idea, over-inflated tires? What pressure are you running?

 

Update:

I checked the steering column and couldn't find any play between my steering wheel and steering shaft so I am going to rule that out.

I had a friend get in and wobble the steering wheel while I looked at the steering rack and the tie rods definitely seems to be out. I think the inner tie rods and the shafts that come out of the rack are both worn out.

I didn't feel comfortable with the steering rack at the junk yard even though it would have been $50. The guy said it had 148k on it, came out of a truck that was rolled over, looked like it had been seeping fluid for some time, and there were no tie rods to go with it.

At this point I am pretty sure I need to do the inner tie rods and the rack as well. I might look for a shop to rebuild my steering rack instead of buying a remanufactured one. If I do the tie rods... will I be able to get the tires close enough to aligned to last a day or two before I get it aligned?

Thanks for all the input.

 

^^^pressure is only 32 psi and they are P rated tires^^^^

 

Should be..

I did my inners today with the intention of driving it to work after I got it aligned. It was too late on a friday afternoon and they wouldn't take my truck in. I thought about just driving it to work but decided I didn't want to risk messing up my brand new $1200 tires.

You can do the tres with the tires on the ground. So in reality there isn't a huge chance you can screw it up too badly. My truck drove nice today without too much wandering or symptoms that the toe was bad. But again, didn't want to risk messing up my tires.

I'd suggest also replacing the outer tie rods while your at it though. The past couple times I've messed with the outers I've had a hell of a time getting them torqued back down. Thus, the second to last time I messed with them I ended up replacing the outers out of necessity. Today I got lucky and was able to get them torqued down again.
Don't forget the small 2 jaw puller to get the tre out of the lower knuckle. Will save a lot of time versus trying to just muscle the things out.

 

UPDATE:

I installed the remanufactured steering rack I bought a couple days ago and am having issues with the fluid. I put the new rack in, hooked everything up, topped it off with Castrol Import Multi-Vehicle ATF for use in Honda, Toyota, Nissan and other imported vehicles (recommended by the clerk at parts store). There is a great whine with the power steering pump and now the fluid is foamy in the reservoir.

What gives?

The fluid the clerk gave me says it meets the requirements of DEXRON III H and prior. Is this the wrong fluid? Am I missing something? I tightened down the lines going in to the rack adequately. Is it normal for this to happen since there would be so much air in the new steering rack?

P.S.
Once I topped the fluid off with less than 1/2 a quart the fluid level is not going down at all after I turn it on and run the steering wheel back and forth several times... I would imagine it would take a lot more than 1/3 a quart or so to fill it up.

 

UPDATE:

This thread can die now. After a lot of bleeding of the power steering system I finally got it to cooperate and push all the air out and it is functioning fine. The truck is at Brakes Plus getting an alignment.

 

Don't forget to check your pan hard bushings. Any play in the rod will really make your Runner feel tipsy, sway and wander all over the road.