psychsurf Posted December 25, 2007 Share Posted December 25, 2007 This just started. I noticed this morning on the way home that there seemed to be a very slight vibration at highway speed. When I hit the last light and turned down the road to my apartment, the vibration became SEVERE at very low speed, then went away entirely. Also sounded like a scraping sound at the same time, but it was hard to tell because the vibration was so loud. Plus, it came and went. I just went back out there and drove it around the block again, and it really comes and goes like an on/off switch. When it is vibrating at 10-20 mph, it sounds like the whole car is going to shake apart, and then it goes away for apparently no reason at all and sounds perfectly normal. It definitely sounds like it is coming from the rear, and I definitely haven't done any recent work back there. I crawled under and wiggled what components I could and nothing seems loose. Next thing is to jack it up and see what wiggles... Can't find my jack right now, doh! Anyway, just wanted to see if anyone had any ideas of a direction I should be looking for this. Oh, also, I don't know if this is related, but the inside edges of my rear tires are definitely more worn than the outsides, and you can see how they are tilted (canted, cambered?) in at the top. Could this have anything to do with it? Maybe a wheel bearing issue or something? I did lay my hand on the rear hub when I first noticed it and didn't feel any heat coming off. Link to comment Share on other sites More sharing options...
edrach Posted December 26, 2007 Share Posted December 26, 2007 Does the vibration come and go with when you accelerate? E.G. it vibrates when you are on the gas and accelerating, but it instantly stops as you let off the gas and coast. If this is the case, it's a bad DOJ (inner joint) on one or both axles. Classic symptom for a bad DOJ. Link to comment Share on other sites More sharing options...
psychsurf Posted December 26, 2007 Author Share Posted December 26, 2007 Nope, no response to throttle, no response to clutch, no response to brake. It's like its completely independent.. Like I said I haven't had a chance to jack it up and wiggle it yet, but it almost feels like loose lugnuts. Of course, if that was the case, I think (think) I would have been able to shift the wheels on the lugs when I was shoving it around with 4 wheels on the ground, but maybe not. It seemed like a surprisingly high frequency rattle for the speed I was going, almost like a machine-gun. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted December 26, 2007 Share Posted December 26, 2007 I say DOJ as well. GD Link to comment Share on other sites More sharing options...
psychsurf Posted December 26, 2007 Author Share Posted December 26, 2007 Are there corroborating symptoms for a DOJ, or is it diagnose by replacement only? I grabbed and wiggled the rear half-shafts, and they seem tight to me, but again I don't really know. And is this something that would have just started out of nowhere like that, no slow failure or anything? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted December 26, 2007 Share Posted December 26, 2007 It would be a front half shaft - not a rear. You probably wouldn't be able to feel anything. You can pull back the boot and look at the condition of the grease. I've noticed that severe DOJ vibration is often caused by lack of grease IN the joint. It's either all leaked out into the boot because it's too runny, or there just isn't enough in there at all. If you add some grease it might go away for a while. GD Link to comment Share on other sites More sharing options...
psychsurf Posted December 26, 2007 Author Share Posted December 26, 2007 It would be a front half shaft - not a rear. Ok, now here's a dumb question... But I'm %90 sure all the action was at my right rear wheel, why would that point to a front DOJ? Link to comment Share on other sites More sharing options...
edrach Posted December 26, 2007 Share Posted December 26, 2007 Are there corroborating symptoms for a DOJ, or is it diagnose by replacement only? I grabbed and wiggled the rear half-shafts, and they seem tight to me, but again I don't really know. And is this something that would have just started out of nowhere like that, no slow failure or anything?A torn boot is often a real sign of failure, but I would think you'd have noticed that. I agree with GD on it's being the front axles although I'm puzzled by the lack of the classic symptom. Link to comment Share on other sites More sharing options...
psychsurf Posted December 26, 2007 Author Share Posted December 26, 2007 A torn boot is often a real sign of failure, but I would think you'd have noticed that. I agree with GD on it's being the front axles although I'm puzzled by the lack of the classic symptom. So, bad front axles can feel like a vibration in the rear? And is there any other way to check them? I'll pull the boot back and see if I can assess the condition of the grease, but as far as I know the two fronts have been replaced within the last few thousand miles. They look like it, too. Link to comment Share on other sites More sharing options...
edrach Posted December 26, 2007 Share Posted December 26, 2007 So, bad front axles can feel like a vibration in the rear? And is there any other way to check them? I'll pull the boot back and see if I can assess the condition of the grease, but as far as I know the two fronts have been replaced within the last few thousand miles. They look like it, too.Boy, I didn't pick up on the vibration being in the rear until now. Sorry. Just to start over, which model do you drive and how many miles on your car? Automatic or manual transmission? I don't think I'd pull back the boots to check the grease. I've never needed to do that and you may create another problem doing that. Link to comment Share on other sites More sharing options...
85T-REX Posted December 26, 2007 Share Posted December 26, 2007 It does sound like a bad rear shaft joint. It's better to check with the wheels off the ground though so it isn't bound in any way. Link to comment Share on other sites More sharing options...
xbalancex7 Posted December 26, 2007 Share Posted December 26, 2007 I'm sure you DID check the lugnuts definitively too? intermittant problems are hard to diagnose, but maybe eventually it will get bad enought to stay constant that is the only beauty in a solid definitive symptom. Link to comment Share on other sites More sharing options...
[HTi]Johnson Posted December 26, 2007 Share Posted December 26, 2007 I'd check the rear driveshaft. Jack it up and put one hand on the driveshaft, then one hand on the circle part of the differential, then try to rotate the drive shaft one way and the differential part the other way. Any play equals bad ujoint. Maybe the bolts that connect the shaft to the diff are loose? Link to comment Share on other sites More sharing options...
TomRhere Posted December 27, 2007 Share Posted December 27, 2007 Been thinking towards driveshaft myself. Check all 3 of the u-joints and the carrier bearing assembly. I've had the carrier assembly fail on a few vehicles, they can show some weird symptoms. Frozen bearing, broken rubber, or broken mounting bracket are things to check for. Link to comment Share on other sites More sharing options...
psychsurf Posted December 27, 2007 Author Share Posted December 27, 2007 Jacked it up and fiddled with it yesterday afternoon. The only thing I could find that seemed like it wasn't "right"... Other than the alignment, of course... Was the carrier bearing. It doesn't look broken or anything, but it was the only part of the whole drivetrain that had any play in it at all. I could shift it probably 1/8" to 3/16" in each direction. But it just felt like the rubber was giving, not like it was seriously slopping around in there. After finding that, I took it out for a drive again to see if I could more accurately pinpoint what kind of sound it was making and where it was originating, and guess what? No vibration. It was starting and stopping spontaneously the day before, and now I can't get it to do it at all. I really hate intermittent problems. Link to comment Share on other sites More sharing options...
joostvdw Posted December 27, 2007 Share Posted December 27, 2007 you did say your front axles were replaced in the last couple thousand miles, with what brand did you replace them? NAPA axles and the like are known to sometimes fail unexplainable within the first few miles. Some people never have any problems, some people constantly bring them back for replacements, so check them out. Link to comment Share on other sites More sharing options...
zyewdall Posted December 27, 2007 Share Posted December 27, 2007 Sounds like the symptoms I had when the driveshaft center carrier bearing went out -- light vibration on the highway for about a year, then finally, it got worse, and from 0 to 10mph was horrible noisy low speed vibration -- as if a whole wheel was loose or something -- and the shift levers would bounce up and down. Turns out the carrier bearing just wasn't any more - so the middle of the driveshaft sagged at low speed, till centrifigal force straightened it out at higher speeds. Z Link to comment Share on other sites More sharing options...
psychsurf Posted December 28, 2007 Author Share Posted December 28, 2007 So, since that's the only thing I'm finding thats fishy at all... Where do you get a new carrier bearing and the rubber that goes around it? Link to comment Share on other sites More sharing options...
zyewdall Posted December 28, 2007 Share Posted December 28, 2007 So, since that's the only thing I'm finding thats fishy at all... Where do you get a new carrier bearing and the rubber that goes around it? I just put in a used driveshaft, either $50 or $100 I think. I am not actually sure that you can get the carrier bearing off the driveshaft, which was why I elected for just replacing the whole thing. Maybe you can though. Link to comment Share on other sites More sharing options...
psychsurf Posted December 29, 2007 Author Share Posted December 29, 2007 Nice. Really wishing I lived near some good subaru junkyards. Link to comment Share on other sites More sharing options...
zyewdall Posted December 29, 2007 Share Posted December 29, 2007 I went to superrupair and ordered a used one -- they ship used parts all over, but shipping would probably kill you on something like a driveshaft though. Link to comment Share on other sites More sharing options...
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