intermittent vibration like wheel out of balance but that's not it

[bbenton8]

A week ago my 2000 Forester (~226k miles) started shaking/vibrating off and on when up to about 50-55 mph & more pronounced at 60-65; just like an out of balance wheel. I have 2 sets of tires (mounted), summer & winter, so put my winter set back on yesterday and a fairly long test drive went smoothly. But a drive later yesterday had the same vibrations again, so I knew it wasn't the tires. I do not hear anything like metal grinding, and the vibrations come and go- sometimes they are very pronounced for a few moments then subside, and generally under 50 or 45 there is little to no hint of vibration. It's hard to pin down where the vibrations are coming from but I kinda want to say toward the rear; there is no steering wheel shaking at all. Any ideas? Many thanks. I can do most work on the car myself (did the head gaskets a couple months ago) unless specialized large tools are required.

[sparky11]

Check the center drive shaft u joints and carrier. Also could be a bad CV joint on a front or rear half-shaft, usually inner.

[nipper]

Yup thats a driveshaft sympton. Check inner tie rod ends too.

 

 

nipper

[bbenton8]

thanks to both of you. Please pass on any pointers as to what/how exactly I should check these items. Can I get the car up and check by grabbing the drive shaft & other parts and pulling/pushing to see if there is play? If it is a U joint or carrier or inner tie rod, anything special to know about replacing it/them?

[bbenton8]

I referred to my Haynes guide, which served me well for replacing the head gaskets. The vibration is based on the same vehicle speed, not the same engine speed, so looks like I might need a new driveshaft assembly. But first I'll get under it and see if I can find play in the U joints & center bearing. Doesn't look like a very hard job, probably the worst part will be removing the 4 flange bolts & 2 bearing bolts that might be pretty tight...

[nipper]

I referred to my Haynes guide, which served me well for replacing the head gaskets. The vibration is based on the same vehicle speed, not the same engine speed, so looks like I might need a new driveshaft assembly. But first I'll get under it and see if I can find play in the U joints & center bearing. Doesn't look like a very hard job, probably the worst part will be removing the 4 flange bolts & 2 bearing bolts that might be pretty tight...

 

 

Ah yes grasshoper ...

 

You can look for play in the universals, but you need to take them down and see if they are seized. Mine had a lot of play in them, others had them seized.

 

The innner tie rod end is a little tough. It doesnt take much play, in facct the play may be almost impossible to see. New inner tie rod ends are a really tough to move around, and i mean tough (in the ball socket). Worn ones will just flop around. If you a torn boot on the tierod end, odds are it is shot due to age and mileage. The traditional way to look for lay through observation is really hard on an inner. The boot hides any visiual play unless it is really OMG bad. YOu can jack up that corner of the car and wiggle the wheel while watching the tie rod end for any play. If the inner is really bad you may be able to feel it.

 

nipper

[davebugs]

I had a 97 GT with the same issues.

 

Ended up being the LF axle. After I started looking and poking around it did have a little "extra" play.

 

So while you're under there you may want to yank on the axles as well to check for play.

[edrach]

A week ago my 2000 Forester (~226k miles) started shaking/vibrating off and on when up to about 50-55 mph & more pronounced at 60-65; just like an out of balance wheel. I have 2 sets of tires (mounted), summer & winter, so put my winter set back on yesterday and a fairly long test drive went smoothly. But a drive later yesterday had the same vibrations again, so I knew it wasn't the tires. I do not hear anything like metal grinding, and the vibrations come and go- sometimes they are very pronounced for a few moments then subside, and generally under 50 or 45 there is little to no hint of vibration. It's hard to pin down where the vibrations are coming from but I kinda want to say toward the rear; there is no steering wheel shaking at all. Any ideas? Many thanks. I can do most work on the car myself (did the head gaskets a couple months ago) unless specialized large tools are required.

One question: If the vibration starts while you have positive throttle (i.e. slight acceleration) and stops instantly when you let off on the gas and comes back when accelerating again I would bet on the inner (DOJ) joint of one of the drive axles. While you are under the car check the DOJs on both sides for a torn boot and/or excessive play. I have seen DOJ failures that are so slight it just feels like wheel vibration (except it goes away when you let off on the gas) and so bad that it feels like the transmission is about to fall out of its mounts:eek:. My bet is on an axle.

[nipper]

One question: If the vibration starts while you have positive throttle (i.e. slight acceleration) and stops instantly when you let off on the gas and comes back when accelerating again I would bet on the inner (DOJ) joint of one of the drive axles. While you are under the car check the DOJs on both sides for a torn boot and/or excessive play. I have seen DOJ failures that are so slight it just feels like wheel vibration (except it goes away when you let off on the gas) and so bad that it feels like the transmission is about to fall out of its mounts:eek:. My bet is on an axle.

 

Inners are hard to diagnose, they will drive you nuts.

[edrach]

Inners are hard to diagnose, they will drive you nuts.

You're correct; but the tip off is that they stop vibrating at trailing throttle; the only question then is which side?

[bbenton8]

great pointers everyone. here's a better description of what's going on. There is no vibration or clunking at all going from a dead stop to acceleration. It's completely smooth, and there is no change letting off the accelerator that I've noticed but I'll pay more attention to that today. It's also smooth at speeds up to 50 to 55, when some slight vibration sets in- usually but not always. If vibration does start, then ~65mph is the most intense, and there can be brief periods where it get's more intense then abates. I'll also pay more attention to whether that higher intensity abates just when reducing speed, and/or when turning the steering wheel. When I slow down to 50 or below the vibration stops. Last evening I followed the Haynes suggestion of getting up to the speed where vibration is worst (65 for this), noting the RPM, then shifting gears and noting if the vibration stayed the same at the same MPH or RPM, and it was at the same MPH that the vibration was noticeable. According to Haynes, "if the vibration decreases or is eliminated...in a different gear at the same engine speed" (another way of saying different MPH) check the following- bent/dented driveshaft; built-up dirt etc on driveshaft; worn u-joint bearings.

 

I just started noticing the vibration last Monday or Tuesday, it was extremely smooth till then..

 

DOJ = double offset joint?

 

If it is the drive shaft, I found one online source- http://www.wholesaleimportparts.com, $372.50 w/ $60 core and they pay shipping including the core. Anyone have experience with this outfit, or suggest another?

 

I just re-read edrach's post and that did jog my memory- I bought the car in Sept or Oct of 2008, and the left front boot was torn, had to have it replaced to pass NYS inspection that December. I've put a good 20k miles on it since. So would the symptoms I describe possibly point to a DOJ/axle?

Edited May 10, 2010 by bbenton8

[nipper]

Im going with again a driveshaft. Next time it happens put your hand on the center console, it should feel strongest there.

 

http://www.driveshaftspecialist.com/

 

Thats who I would recomend. Many have used them with no issues.

 

Now sometimes time is your best diagnostician. The driveshaft is no where near falling out of the car yet. If it is the driveshaft, soon the speed it starts at will drop to 60, then 55, then 50.

 

If it does drop down (and it will) you have your answer.

 

nipper

[edrach]

Now sometimes time is your best diagnostician. The driveshaft is no where near falling out of the car yet. If it is the driveshaft, soon the speed it starts at will drop to 60, then 55, then 50.

 

nipper

Nipper is correct about time is on your side (and perhaps on the driveshaft also--I've never had driveshaft problems but have seen the DOJ syndrome many times in the last 10 years). Neither the driveshaft or DOJ issue will leave you stranded without warning. Both possibilities will get significantly more severe with time which should point you to the correct solution.

 

Update: Actually I have had a driveshaft issue once with our Impreza. Local shop diagnosed it for me quickly (thank you Pacific Import Auto). After test driving it, they put it up on the lift with the engine running and a tech in the car. Put it into first gear and let the engine idle. You could actually see the driveshaft vibrate as it turned. A trip to the local pull a part yard and a couple of hours under my car and the vibration issue was resolved.

Edited May 10, 2010 by edrach

[edrach]

If it is the drive shaft, I found one online source- www.wholesaleimportparts.com, $372.50 w/ $60 core and they pay shipping including the core. Anyone have experience with this outfit, or suggest another?

 

I just re-read edrach's post and that did jog my memory- I bought the car in Sept or Oct of 2008, and the left front boot was torn, had to have it replaced to pass NYS inspection that December. I've put a good 20k miles on it since. So would the symptoms I describe possibly point to a DOJ/axle?

Reading your posts again, it's obvious that you can do your own work for most of this once you find the cause. Give it time and it should become more obvious.

 

Another consideration is cost. Axles cost about $100 each; a driveshaft is much more expensive. I'm not an advocate of throwing parts at something until it's fixed, but axles are much cheaper than driveshafts.

 

As to the left front boot being torn: was it the inner joint? Outer joint (CVJ) has completely different symptoms when it starts to fail.

[bbenton8]

thanks edrach, not sure about the left front boot, that was awhile ago, don't remember if it was inner or outer joint. If it is a front axle problem, would that not cause vibration/shaking in the steering wheel? or not?

 

I agree about not throwing $ at it, I can't afford that. Next step is to jack it up tonight & get under it.

[edrach]

thanks edrach, not sure about the left front boot, that was awhile ago, don't remember if it was inner or outer joint. If it is a front axle problem, would that not cause vibration/shaking in the steering wheel? or not?

 

I agree about not throwing $ at it, I can't afford that. Next step is to jack it up tonight & get under it.

No, it didn't cause steering wheel vibration the first time I had the issue. The vibration was so slight that an experienced (non-subaru) shop couldn't confirm it; but I knew it was there. A later failure on one of my other cars was so bad I thought the transmission was falling out of the car--still no steering wheel shaking.

 

If you don't find anything visible tonight, give it time; it will become more obvious with time.

[bbenton8]

this turns out to be a "none of the above" answer. I jacked it up & got underneath it a little bit ago, pushed & pulled on the driveshaft & all 4 axles, & didn't notice anything obviously loose. Then I pushed on the wheels while raised, & the fronts and right rear were solid, but the left rear shook back & forth a great deal. My mechanic (who is good) replaced the bearing on it late last year, the wheel shook the same back then before the bearing was replaced (but there was just a clunking sound back then, no vibration). Seems the replacement bearing must have been defective, I haven't put too many miles on it since, just commute since January when I got my new job. So I called him and dropped it off just now, we'll see what he has to say. He's a good guy so I'm keeping my fingers crossed this won't cost me. We shall see!

[edrach]

this turns out to be a "none of the above" answer. I jacked it up & got underneath it a little bit ago, pushed & pulled on the driveshaft & all 4 axles, & didn't notice anything obviously loose. Then I pushed on the wheels while raised, & the fronts and right rear were solid, but the left rear shook back & forth a great deal. My mechanic (who is good) replaced the bearing on it late last year, the wheel shook the same back then before the bearing was replaced (but there was just a clunking sound back then, no vibration). Seems the replacement bearing must have been defective, I haven't put too many miles on it since, just commute since January when I got my new job. So I called him and dropped it off just now, we'll see what he has to say. He's a good guy so I'm keeping my fingers crossed this won't cost me. We shall see!

I won't be insulted if it falls into a "none of the above" category. I'm perfectly willing to learn and connect new informtion with symptoms. In any event, thank you for the feedback and let us know what finally fixed it. It's so good when an OP reports back with the actual fix. We all learn from it.

[nipper]

No no no it has to be A B C or D

 

None of the above was NOT an option.

 

hehehehe

 

rear wheel bearings are fairly robust, which is why sometimes we forget about them, including me.

 

 

nipper

[bbenton8]

@ nipper- Ha Ha! @ edrach- sharing knowledge is always good! But I'm not considering any solution "in the bag" until I get confirmation from my mechanic that the new bearing failed.

 

Once some things settle down I plan to write up a summary of my experience doing my own head gaskets, it really wasn't all that difficult and I learned a lot. Among other things, I'm a certified K-12 technology teacher so I believe in passing on the knowledge!

[edrach]

@ nipper- Ha Ha! @ edrach- sharing knowledge is always good! But I'm not considering any solution "in the bag" until I get confirmation from my mechanic that the new bearing failed.

 

Once some things settle down I plan to write up a summary of my experience doing my own head gaskets, it really wasn't all that difficult and I learned a lot. Among other things, I'm a certified K-12 technology teacher so I believe in passing on the knowledge!

Thank you for the thought and planned follow-up. So often here on the USMB there's an effort to fix a problem and then an omnious silence without a final solution. Thanks for planning on following through. Regardless, hopefully the issue is repaired soon for you.

[nipper]

Among other things, I'm a certified K-12 technology teacher so I believe in passing on the knowledge!

 

What does twitter and facebook have to do with headgaskets

 

[edrach]

So whatever happened with this? What fixed the vibration?

[bbenton8]

I believe it's on the 2nd page of this thread- left rear bearing spindle worked loose. The mechanic who replaced the bearing last fall fixed it, no charge. Running smooth now.

[edrach]

I believe it's on the 2nd page of this thread- left rear bearing spindle worked loose. The mechanic who replaced the bearing last fall fixed it, no charge. Running smooth now.

Sorry I missed that. Learned something new with this one. Thanks.