Hi guys, I'm looking for some advice. I consider myself a pretty decent mechanic, been turning wrenches for around 20 years and have many certs to go with it but I don't do it as a trade anymore.

Anyway, my wife's 2008 Legacy GT has had a vibration or "shimmy" that has been there since we acquired the car. I thought new tires and good balance would fix it but I was wrong. It occurs exactly at 62-65mph and seems to come and go... I've rotated the tires, checked for bent wheels etc. I've went up with air pressure and down. I've checked for wheel bearing play and tie rod play. Nothing in the front end seems loose. I'm convinced it is NOT the wheel/tire as it is still occurs exactly the same speed no matter which tire it where and done it with the old tires.

The only fault thats visible that I haven't addressed yet is a torn CV boot on the passenger side. I have a new axle and plan to do that this weekend.

Brakes and rotors were replaced with new powerslot kit about 10k miles ago. I'm getting ready to just rip the entire front end apart and replace everything but I'd like to avoid that if necessary...

Bent or worn axle

But in my years of experience, a bad CV axle usually only rears its head on hard acceleration or sharp turns, neither of which mine does.

Inner CV joint problems can cause this on some Subaru, the boot looks perfect but the grease has turned to oil and the joint worn out. Did you check for rack play, internal movement and the mounting bushings?

Bad engine mount.

Could be a few things..im a subaru guy..or was.

If its an aftermarket CV shaft there were issues with them not being balanced properly that was yrs ago.

Sticky or frozen caliper/piston

Bad hub or wheel bearing

Ball Joints

Bent Rim

I would listen to the 2 answers from the seasoned mechanics - and they point to an axle related issue.
Chris142 and Trav

This problem has been on going since the car was new and the Stealership never fixed it? I guess that's just one more reason not to buy a Subaru they ignore to many warranty issues.

Johnny, way to jump off the cliff without reading the details... he said it was present "since we acquired the car". Nothing mentioned at all about buying it new. And Subaru obviously isn't as horrible as you make them out to be, they've been awarded the vehicles with highest resale value like 3 times out of the past 5 years... people aren't willing to pay top dollar for used pieces of junk. Not like a new Dodge minivan, which loses something stupid like 83% of its value in the first 5 years...

OP, I had the same issue on my Odyssey two years ago, which showed up when I had snow tires on. At first, I thought it was the tires, so I rotated and rebalanced them to no avail. I called my brother who is also a mechanic, and said essentially the same thing as Trav; inner CVs. I checked and none of the boots were torn, but the vibration was getting pretty bad. I had both axles replaced, and voila, no more vibration at any speed.

Looks like car was purchased 1/15/17:

I had a similar issue on my 2000 Dodge GC some years ago. Was the original axle with 120k on the van. It looked fine. Finally, the boot cracked and it started slinging grease. Replaced with a new shaft and there was no more weird stuff. In my case it was the right shaft.

YMMV

Wayne

Yes car was purchased used- not new so no dealers involved.

I'm going after the axles this weekend so we'll see what that brings, thanks for the tips/advice gents!!

Overall, I love the car, it has 150k on the clock now and nothing has been done other than the turbo replacement when I bought it. (why I got it so cheap) It handles great, runs very well and is a blast to drive with the 5 speed.

I have 3 of those OE axles sitting right in the garage waiting for new inner joints (outer are perfect just reboot job with poly) I ordered from Europe. Every one of them a lube fail on the inner, perfect boots.

Just a heads up.. If it's an AT legacy, I've heard that people have vibrations at idle with aftermarket cv axles. I understand that's not your current issue, but if you're putting an aftermarket in this weekend, that could happen. The vibration occurs when stopped in drive, but goes away if you shift into neutral.

Not sure what the culprit might be for your current vibration issue.

I replaced both left and right side torn inner boots with Dorman universal silicone CV boots as they claim silicone is more heat resilient to poly boots. So far it has not torn after 1 year or 12K miles. It was for a 06 Outback with 95K at the time. The reason for boot replacement and not entire axle replacement was for the reasons posters mentioned above with aftermarket axles creating vibration or fitment issues plus cost. Allwheeldriveauto.com has an excellent write up just for this repair. Also, two well respected youtubers, south main auto and pine hollow diagnostics have videos depicting using OEM and not aftermarket axle replacements too. I followed pine hollow diagnostics video to separate the joint but keeping the green cup coupled to the transmission case. Maybe investigate if your axles were replacements with aftermarket too before you purchased car and systematically eliminate potential causes of your vibration issues.