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Suby Outback "shakes" while accelerating

I have a 2002 LLBean H-6 Outback. (125, 000) Recently I’ve notice while I accelerate and the needle is on or near 20 mph, the car shakes for about two seconds. It doesn’t continue as I accelerate or decrease in speed.

I have had the front left wheel bearings replaced TWICE in the last 6 months including the the whole steering neck the second time.

Could it be that the front right wheel bearing is going out at the same time? Is the transmission starting to go?


Sorry Tim, but there’s too little here to make a guess.
Is it shaking in the steering wheel or the whole car?
Have you had a shop look at it? What did they say?

Possibilities include but are no limited to
an overdue sparkplug replacement,
a bad CV joint,
a bad motor mount,
a bad torque converter (if it’s an automatic)
a bad clutch (if it’s a manual)
and a few other possibilities. I’m sure others will add to the list.

If the shaking is brief and speed specific/RPMs specific, I think that you can rule-out a wheel bearing.
However, it is entirely possible that the transmission is the source of the problem. If this shaking takes place briefly at ~20 mph, that might mean that second gear in your transmission is malfunctioning.

Why not try shifting manually? If the shaking takes place when you shift to second gear, and stops when you shift to third gear, then I think that your next course of action should be a visit to an independent transmission shop. Ask friends, neighbors, relatives and co-workers for recommended shops.

Whatever you do, do NOT take the car to Lee Myles, Cottman, Mr. Transmission, or (God forbid) AAMCO–unless you want to be overcharged for substandard workmanship. Look for an indy trans shop that has been in business for at least 3 years.

Mountainbike has provided some other good suspects, but you can rule-out a bad clutch, as the only transmission that was available with the 6-cylinder engine was the 4-speed automatic.


Thanks for the Tips. It is an automatic. It doesn’t feel like it missing out like a bad plug would do. And no there’s no shaking in the steering wheel , just a slight shake or vibration. I’m thinking a CV joint- My 2001 Outback might have had the same problem at one time.

In regards to the torque converter- I thought these engines were supposed to last forever? Wouldn’t 125,000 be a little early for that?

That would be referred to as a “myth.”


The torque convertor and the engine are two separate things. Last I checked was that mechanical things break and electrical things can fail.

The terms are interchangeable.
A mechanical part or system that suddenly breaks in use in a manner to render it totally unserviceable and unrepairable is said in engineering circles to have suffered a “catastrophic failure”. And if an electrical system fails it’s commonly said to have “broken”. If it totally stops doing its job while in use in a manner that destroys it, it too is referred to as a “catastrophic failure”.

The torque converter is part of your transmission.
The ultimate lifespan of both engines and transmissions is directly related to the maintenance that they have received. How often have you changed the trans fluid and the trans filter?

After 15 years/125k miles the trans should have been serviced 4 or 5 times.
Was it?

And the manner in which they’re used.

And, we have no idea at this point regarding either the maintenance of this vehicle nor the way that it was driven.

Automatic transmissions have something called a lock-up torque converter. Its designed to lock up and act like a car with a clutch at a certain speed/rpm, in order to improve mpgs. Otherwise it would be like auto transmissions of the past and slipping all the time even at freeway speeds and reduce your car’s mpg, and damage your wallet with increased gas costs. Sometimes that feature can go awry and cause a shaking sensation. What happens, it can’t decide whether to lock or not and jumps back and forth between the two states, resulting in the car shaking a little. On some transmission it is possible to disable that feature as a way to test if that’s what’s causing the problem. Anything’s possible of course, but this doesn’t sound like a wheel bearing problem to me. I should mention that torque converter shaking is usually reported to occur in the 35-50 mph range here, usually not in the 20’s.

…which is why I don’t believe that the OP’s problem lies in the torque converter lock-up mechanism.