Hi,

I have a 2005 GX470 with about 50K miles. Over the last few weeks it started exhibiting a weird problem. When accelerating above 20-25 MPH it starts shaking. Not the steering wheel. The entire car is shaking as if driving over rocks. It is pretty annoying, and I am now concerned as it seems to have gotten somewhat worse than before.
Tires are rebalanced and rotated, so i dont thing it is that.
My wife is freaking out, as she is driving it with 2 small kids. Any thoughts? Ideas? I'd like to be prepared before i take it to the dealer.

Thanks in advance.

I never had shaking problem, but I had similar. In my case it was bad rotors. Also did you check if your air suspension working properly.

Could be the driveshaft threw a weight as well?

oh man, i just read about something where the driveshaft gets out of balance. It was a tsb i believe. Mann777 knows about it.

Thank you all for replies!!

I am now suspecting air suspension. I turned height control ON/OFF a couple of times and problem went away. Unfortunately that lasted less than a day. The symptoms are there again, although not as bad as before. Could it still be a driveshaft?

I hate going to a dealer and dealing with "could not duplicate the problem" response...

Thank you again!

Its hard to tell without driving. Is your car out warranty?

I have about 2 mo of extended warranty left.

First I would insist on replacing Drive shaft. First time I went to a dealer he refused to replace. So I went to the second one and he was more then glad to replace it. He said he is full aware of the recall. If that doesnt help I would check your brakes. Make sure you dont have wraped rotors, and your brake pads has even wear.

I would take it in and take the mech for a ride--seems like it vibrates pretty consistently now. When he can feel that then maybe experiment with the air suspension with him in the car as well--that way you can sort of set him the right direction..lol

The way I look is your truck has been more in the garage and less driven with year model quoted, neverthless, to me this look to more of a Steering flutter and that causes the whole truck to vibrate while driving on highway, This is caused by flat spots that normally develop in the tires after sitting for long periods of time. Check it out. To correct it if the defect is found, then you have to goto the dealer and quote the TSB-
ST002-05. Most of the 04/05 Models were affected.hope this helps

Thanks for all the replies!
I bought the truck CPO with VERY low miles. Has been driven on avg 10-12k/yr since then. Tires are 8 mo old. Had brakes checked out about a month ago. I guess it is time to go to a dealer...

Sounds like the driveshaft issue. Mine had it too but at the common 60-65 mph range.

Well... I finally made it to the dealer. They tell me that front right caliper "started to seize". Got it replaced under the warranty, but honestly, i dont think this is what the problem is. For all my other complains, i got the expected "could not reproduce the problem"

Mine ended up being a balance issue that only a "ROADFORCE" balance would cure. It was cheap too...$99 including a 4 wheel alignment at Town faire tire. Smooth as glass now.

From my point of view, I believe you have a leak in rear air suspension.
You are feeling up/down shaking (not a vibration) as you taking off, like a bad shocks or no shocks, riding just on springs.
Some days are good, some days worse.
Try to cycle your ride height before taking off with it first start up every day and you not going to feel it again.
Start it up, push the High button, let the compressor pump for about 10 seconds and push the Low button. Suspension light on dash will switch from H to Normal and it will blink till the cycle is finished, light will stay on and ride height is normalized. Whole cycle will last maybe 20-30 seconds.
I have the GX just for 2 months and I have to do this ones or twice a week other wise you can feel any road inperfection or every little rock you drive over.
Try it and see, if this will fix your vibration.
Good luck, Bernard