Our 13 Outback has an issue and the collective is always my first choice for opinion.

At around 80 on the interstate it tracks smooth in a straight line. As soon as you give ANY steering input, left or right, there is a pronounced shudder that stops as soon as you straighten out again. It is far less pronounced or non existent at slower speeds. Tire wear looks even and we’re rotated about 2 months ago when all 4 wheel bearings were replaced. Let me know what you think.

This message has been edited. Last edited by: gearhounds,

When did it start happening? Can you verify all tires are the same circumference?

My guess would have been faulty wheel bearings. Perhaps a botched install or a parts failure?

No issue at lower speeds?
Any noises while turning?
Maybe something with the P/S pump, if it only happens with steering input, but no issue when cruising straight & level.

Gen 4 has a dedicated forum section for shakes

https://www.subaruoutback.org/...el-shake-issues.108/

Start small, you said tire wear looks good so I imagine pressure is good too? What about fluid level and quality? Doesn't sound like air in the system if it's not making noise(s). Could also be a serpentine belt coming loose at high RPM which would affect the pump operation. Take a good look underneath at CV joints and ball joints, if they're worn it could induce vibration. Last time the wife's 2012 Outback was at the dealer they said the lower control arm bushings were cracking and needed replacing. They wanted an exorbitant amount of money to replace them so I just bought aftermarket lower control arms which came with the bushings and ball joints pre-installed and did it myself. Obviously anything that's worn or out of tolerance in the suspension/steering system can cause problems.

Steering rack mounts?

Change the rear differential gear oil, particularly if it hasn't been done within the last 30K miles. Use the Subaru oil.

Just got done with a furniture moving project and got a chance to look at the replies.

I had a similar shimmy a few months back that only manifested itself above 80 mph; then in came on strong enough to be a concern. I took it to Subaru and the drivers front bearing was very worn, and passenger front and drivers rear were moderately worn. Since I was about 35k past the bearing life expectancy, I had all four done. This seemed to cure the shimmy...for a spell.

Now the shimmy is again hitting right around 80. As I said, tracking straight is smooth but even fractional input to either side and the shimmy starts up. I haven’t had the tires balanced in some time but I would expect them to shimmy going straight, not just in a gentle turn.

My first impulse is to suspect something is amiss in the steering geometry. Our Subaru shop (Winchester VA) is a good honest bunch so I believe they’ll run it down. If they botched the bearing job, they’ll make it right but I don’t hear any odd noises so I’m guessing they didn’t.

If it tracks straight on the road, I would think the tie rod ends would be ok but I would certainly check them.

You might also rotate the tires again to rule out problems there.

Front bushing in the lower front control arm? I've seen those bad and creating odd symptoms. Just shaking the wheel often doesn't reveal it. With the car jacked up under the body so the suspension hangs free, take a screwdriver or pry bar (it doesn't need to be a big one), wedge it between the control arm and its mounting bracket and push/pull. A bad bushing will move easily.

Coincidentally, the last one I saw bad ('14 Forester) was found while replacing a front wheel bearing.

I've had to do cv axles and wheel bearings on my 2014 Crosstrek. Knowing what they do to check for bearing play on the lift, my bet is the bearings could impart that sort of behavior. I love almost everything about my Subaru, but have come to terms that their materials are a little on the soft side for corrosion resistance.

Another vote to take a hard look at the front control arm bushings. A Subaru specialty shop would be my choice, even if it meant a road trip.

Update- the verdict is the lower control arm rear bushings- evidently a rare occurrence as the shop can only collectively remember about 10 such failures. At 140k on the odo, I’m not having too much heartburn if it solves the shimmy.

At 72k I did front control arm bushings, front pads & rotors, and new tires. It then drove and tracked like brand new.

Glad to hear they tracked it down.

quote:

Update- the verdict is the lower control arm rear bushings …

Has the repair been made yet, and if so, did that fix the problem? The rear bushing failing is - as said earlier - unusual.

Yes, and it drives like a new car. Well, so much better than before it seems new by comparison.

quote:

Originally posted by egregore: The rear bushing failing is - as said earlier - unusual.

Maybe specific road conditions are particularly rough on the rear bushing over front bushings ...

Reading into specs makes be want to BUY!

SuperPro's complete front lower control arm kit reduces unsprung weight, enhances front end traction, cornering grip, increases steering feel and feedback.

quote:

Originally posted by Woodman:
At 72k I did front control arm bushings, front pads & rotors, and new tires. It then drove and tracked like brand new.

Glad to hear they tracked it down.

I think as a general rule, soft points and shocks are grossly under-maintained in the general population of cars and trucks. Cars are so good now that they can last a very very long time. And with these components replaced, the can pretty much drive like the day they were new. But as they usually just get incrementally worse, it's hard to recognize when is the right time. And it's not SUPER cheap to do, so unless something starts to misbehave like this...

^^^^
This is what I suspect is the case here; it’s a nearly 8 year old car with a bit over 140k on the clock. The block was replaced just before 100k under the extended warranty due to excessive oil consumption (3 quarts in an oil change period), the tranny is solid, and beyond cosmetics seems like new again. It’s paid off so I’ll happily shell out upkeep money to keep it on the road.