So I know that this problem has been discuss many times in this forum; but, I don't know that a definitive cause was ever determined. I have a loaded 2008 GX with 213000 miles on the clock. I bought the vehicle with just under 190K and had to replace the alternator & rotors and just recently the replaced the secondary air injection pump @ $2200 at my Lexus dealer. When I bought my vehicle I noticed the steering shake during my test drive on a nearby interstate segment. However, I had test driven other used GXs and had similar experiences ...so at the time I assumed it was just the patch of highway I drove over.

Like many others on this forum had reported, the shake seems most evident at approximately 65mph. What's interesting is it not always consistent. For example, when its very cold (below freezing), I never experience any steering wheel shimmy. There are some days where the same stretch of highway doesn't produce the shake during warmer weather but other times it does. At times though, the steering wheel vigorously shakes -- you can see it visually. My Lexus dealer looked into the problem once, that's when I had the rotors replace (because they were bad) and they road forced balanced the tires. But the shake was still there, they even told me the road force didn't resolve the problem. I needed my vehicle back at the time so I didn't pursue it. Now my kid is heading off to college 800 miles away and unfortunately I'm told we can't take our 2014 GS AWD with luxury package cause we have to take a lot of stuff for my son's dorm room -- including mini fridge (really?). I guess the good news is that above 70mph I really don't feel the shake ... but their are times where I'll need to drive 65mph...and I'm not looking forward to the beating.

So I'm tempted to take it to my Lexus dealer and have them resolve it...but again was curious if this forum ever made the determination of the cause. Personally, I don't think its the tires, wheel bearings or CV axle, etc...cause I would think other parts of the car would shake (e.g. dash, door, etc) -- but they don't, only the steering wheel.

 

so went to my local Lexus dealer to consult with the my service advisor; He indicated that GXs do have a slight shimmy but it really shouldn't be that noticeable. The master mechanic suggested that we go for a drive. He indicated he could feel the shimmy at even at low speeds. And he could definitely see that it was pronounced at 65mph. He believes it's a belt shift in the tire. They checked out the suspension and said there was nothing they could find that would cause the shimmy -- just normal wear. So I'm going with Bridgestone Dueler H/L Alenza Plus. I'm supposed to have it back later today...I'll let you know how it turns out.

 

 

Ok, case closed. No more shaky wheel. I would have never suspected that tires would make that much of a difference. I truly thought that the repair would be much more involved.

I changed my mind at the 11th hour on the tires. After reading Tire Rack consumer feedback, I went with Michelin Defender LTX M/S instead of the Bridgestones. They checked my alignment as well and indicated that my GX470 was in spec so no alignment was necessary. The tires I replaced were Dunlop Grandtreks which came with the vehicle when I bought it. The GX drives very differently now even at lows speeds, corning, etc. And extremely quiet at highway speeds. Much more confidence inspiring and now a real pleasure to drive.

 

 

 

The $2200 was for the SAI replacement only and just had it done a few weeks ago. I had the rotors and alternator replace about 16 months ago. The work was done at Plaza Lexus in St. Louis

 

Are the Michelin's still working for you? I have the same shimmy and was told by a Lexus dealer to replace my tires with Michelin's. I did... same model as yours. It still shimmys. Usually in the same highway sections and around 65. I'll take it out later today and get it up to 75 at that spot and see if it goes away.

 

So I took it on the road, known to shimmy. It doesn't shimmy with my 4 Runner in that spot (or any) by the way. The tires are Michelin. I had the front end aligned at my Lexus Dealer, (Lexus of Wayzata) and it still does it. It dosen't shimmy at 50, but 65-80 the steering wheel shakes back and forth.

 

This sounds like a separated steel belt in one of your tires.
Try rotating them... see if the shimmy goes away. I know the 4RUNNER I bought drove smooth... I rotated the tires and it started this shimmy in the steering wheel at 65-75mph... the smoother the toad, the worse the shimmy. Also the shimmy was worse when the tires were cold....
rotated them back and the shimmy was gone.... so I knew it was a tire... I’m a technician and when I balanced them.. they were all good... I put it on the road force and it would get under the specified tolerances for a truck.


Working with audis I see this often when a nylon cord in one of the tires breaks. It can occur when installing the tires too... the cheaper the tire... the better the chance that one will beak. Also the cheaper the tire shop, the better the chance. Lol

when I refer to cords and belts... I’m referring to the reinforcement inside of the tires rubber. Just an FYI.