Dear Tom and Ray:

I have a manual-transmission 2000 Subaru Forester with 126,000 miles that I've had since it had 12 miles on it. I also have a 1-month-old baby. As a new mom, my car has me a little worried. During the past year, it has started shaking violently whenever I make a left turn. This starts happening after I've driven it about 10 miles. When I say "shaking violently," I mean it feels like the body is going to rip itself off the chassis. I've taken it to the dealership and multiple mechanics who won't get in the car long enough to feel the problem, so it hasn't been reproduced for a professional. They have all told me, "That's what happens to Subarus with high mileage." I find that hard to believe. Any thoughts? Is it still safe to take on long trips? Thanks.

-- Piper

TOM: Gee, Piper. My 1977 Fiat shakes violently when I drive it, too. But that's how I know it's running!

RAY: You need several things, Piper. First, you need a mechanic who's actually interested in helping you. Try checking the Mechanics Files on our Web site (www.cartalk.com/mechanics). That's a list of mechanics who are personally recommended by other readers and listeners of ours.

TOM: Anyone who won't spend 10 minutes riding with you to see what's wrong with your car is not terribly interested in your business. Or your welfare.

RAY: When you find someone willing to experience the shaking firsthand, I suspect the diagnosis is going to be that you need a new viscous coupling. We've seen viscous couplings go bad on lots of Subarus around the same age as yours.

TOM: The viscous coupling is Subaru's version of a center differential, which allows the front and back wheels of an all-wheel-drive car to turn at different speeds when you're cornering. If it's binding up, it'll result in one or more wheels dragging on the pavement while you turn. You'll feel that as a violent chattering sensation. Sound familiar?

RAY: They usually don't take 10 miles to start misbehaving when they go bad, but that would still be my first guess. If you need a new viscous coupling, it'll cost you in the neighborhood of 700-900 dollars.

TOM: If it's not the viscous coupling, the next thing I would check is your CV (constant velocity) joints. One of them could be binding up. It could be in the front or the back, inner or outer. You've got eight of them.

RAY: And can you still take this car on long trips? I wouldn't. At least not until this is fixed, Piper. If it's the viscous coupling, it can really mess up the car's handling. And if it binds up while you're cornering at a high enough speed, you could even lose control of the car.

TOM: Not to mention that all that shaking will keep waking the baby!