Over the last few years our Highlander has had very infrequent but
> alarming problem of shaking violently at speeds of about 35-45 mph.
> This vehicle only has 47k miles and has been well-maintained. The
> shaking can last for up to a couple of minutes. If we decelerate the
> shaking stops and doesn't happen again usually for weeks or even
> months at a time. People at the service department just give a blank
> look when I tell them about the problem and that I'm worried something
> is wrong with the transmission. They tell me they can't do anything
> without being able to drive it and reproduce the shaking. It happens
> so infrequently I'm not sure how to trouble-shoot it or ask for
> help.
>
> Has anyone else had this happen? Any ideas what it is? I don't want
> to ignore an issue that needs to be fixed and I don't want to be
> stranded going over donner pass later this month. It happened just
> the other day where it was shaking violently at about 40mph and then
> continued to shake as I slowed almost to a stop. It was the first
> time it persisted as I slowed down so I checked to make sure I didn't
> have a flat. The tires were all fine and when I started up again the
> ride was smooth. This is much different than the air pressure waves
> you can get inside the vehicle when the windows are down. It is
> something mechanical. I don't really feel the steering wheel shaking
> and is not associated with braking. Any help?
Wow, is the shaking effected by the load on the power train? I would imagine applying more power to a power train problem would make the shaking much worse.
Is the shaking effected buy the road conditions? Something like a wheel with a totally blown shock can let the tire get bouncing clear off the ground at highway speeds.
Regardless I would be worried about the car not being safe to drive on the road.
GL Dan