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Need help isolating vibrating/shuddering at highway speeds


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95 legacy wagon 2.2l

Ive been diagnosing a high speed vibration for awhile. Its generally not felt in the steering wheel so much as it is felt through the whole car. Initially changing the brake calipers out had helped, as one was stuck and the rest in various stages of getting stuck. Initially that worked for a fee hundred miles... Checked the calipers again, one was stuck again, replaced it. Went away for a couple hundred miles, came back, the calipers are fine this time. Even wear on the pads(all replaced as well).

Ive since done an alignment and replaced all the tires, balanced etc. The rear driver side is scalloping on the inside tread, so i rotated the tires and that didnt solve anything...

So the back struts are dead for sure, i get no play or feed back in the spring when i check for bad bearings... The differential has began seeping, but nothing alarming as far as rate. No odd smell of burning up the rear diff. But the seepage seems to be coming from above and around the other side of the fill plug... There is no oil on the axles what so ever.

The bushings are 50\50. Axles look, feel, and sound fine. I cant really identify a specific noise while driving, as in humming, howling, growling, grinding, but it does seem road noise is loud(er?)

Am i dealing with shitty struts, can i overlook the bearings, should i be trying to check the drive shaft or rear diff 

Is there something i can do while its on 4 stands to check? Ive read other threads recently posted but im not sure my front is to blame as it feels like its in the rear.

It doesnt really care if im turning to the left or right, tight turning is still responsive(i think. Ive never had an awd, so maybe i dont understand what torque bind is etc), no clicking. Its seem to be more prominent at higher speeds, above 70mph, seems to be better when its cold or dark outside(weird?), but once it starts i can feel it all the way back down to 30-40 mph.

Idk. Thanks for any insight.

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10 hours ago, FerGloyale said:

CV axles.  Almost every time.  You can't feel it by hand......Just vibration, especially on throttle/ under load.

Interesting.

Is there a way to isolate it to the axles without pulling off the car and/or blindly replacing them?

Budget is tight, as it time. I still daily use the car.

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3 minutes ago, destey said:

I'm thinking of setting up a little camera under the body by the CV shaft to see if I can see it vibrating. I'm just sick of buying new parts, spending hours putting them in, and it not fixing the problem.

Thats what im hoping to avoid, though honestly if i had the money I would replace stuff until its fixed, if only just know i replaced all the other stuff on the way to finding the problem... But that's not an option right now :p

so yeah i was going to put the car up on jack stands in the drive way and have a friend either watch, or 'drive' the car while i watch/hear, for any vibration in the axles or driveshaft.

ive had a person else where suggest ujoint. And one other suggest its my strut being that being that far gone.

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I doubt its the struts. Bad struts will make it handle a little crapy and bounce after bumps, but not vibrate. By U joint I think they mean the main propeller driveshaft. Which is over $400 and difficult to replace without a lift. Used ones of that era are hard to come by that are in good condition, because the needle bearings in the joints are usually shot after all those years

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37 minutes ago, 1 Lucky Texan said:

I suppose the 'intensity' 'could' decrease with use of the FWD fuse, however, all the same parts will be turning at the same speeds.

Thats what i thought. I got it on stands right now. Just waiting for some warmer rays to see if i can see/hear some shaking somewhere

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Okay. So just 'drove' it on stands, couldnt pin point anything in the driveshaft area, buuuut i noticed my rear 2 tires do not spin. Fwd fuse is not in.

Is my diff locked up?

Also. Makes me lean toward rear axles and one of my rims seem bent.

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Another thing i noticed before i noticed the previous 2 replies. Someone at legacygt forums suggested to turn the drive shaft by hand at the rear diff.

The DS spins relatively easily by hand, and smoothly, and both rear tires rotate with it. But one tire was getting stuck halfway thru rotation.

Checked to see if caliper was stuck, indeed it was, unjammed it, it now glides free. But it still remains. I can hear a grinding esque noise on the opposite side of the rotor from the caliper. But more prominent in the rear of the spindle than the hub side.

I dont think the bent rim is my primary source of vibration, it doesnt seem that bad, and the tire was one the front, where ive prominently felt this experience through the back...

Im guessing this is narrowed down to axle and/or bearing on the rear side vibration.

And as far as the the awd not engaging, maybe the duty c? Because i nothing is locked up? Or am i missing something?

 

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On 6/23/2019 at 10:44 AM, GeneralDisorder said:

You need to put it under a load. Drive it on a lift with the brakes applied to simulate a load on the drivetrain. It is most probably front axle inner DOJ's. 

GD

Is this a good idea? I read somewhere that with load off (ie on a lift) the vehicle the suspensions moves past its limits and can damage the CV axles.  I've done it in the past with other subarus though without harming anything so not sure if that's true or not.

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17 hours ago, Jadu108 said:

Another thing i noticed before i noticed the previous 2 replies. Someone at legacygt forums suggested to turn the drive shaft by hand at the rear diff.

The DS spins relatively easily by hand, and smoothly, and both rear tires rotate with it. But one tire was getting stuck halfway thru rotation.

Checked to see if caliper was stuck, indeed it was, unjammed it, it now glides free. But it still remains. I can hear a grinding esque noise on the opposite side of the rotor from the caliper. But more prominent in the rear of the spindle than the hub side.

I dont think the bent rim is my primary source of vibration, it doesnt seem that bad, and the tire was one the front, where ive prominently felt this experience through the back...

Im guessing this is narrowed down to axle and/or bearing on the rear side vibration.

And as far as the the awd not engaging, maybe the duty c? Because i nothing is locked up? Or am i missing something?

 

I could be wrong but I think mechanically the car is essentially FWD with a second shaft that puts power to the rear axles through a clutch pack for momentary AWD. The cluck pack is normally off and locks up when it detects wheel slip. That's the gist I got from looking at a model of the transmission innards  The 5spd is a little different and functions more as a full time AWD, as the center differential is a viscous coupling that doesn't allow for too much RPM difference between front and rear shaft speed

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9 hours ago, 1 Lucky Texan said:

the little parking brake shoes/gear inside the rear rotor might be making some noise.

Yes i thought that too. But the junk yard here had a legacy with brand new bearings put in before the HG blew :p

25$ a pop for the spindle assembly... So im changing those out regardless to be sure. Also no drag from the ebrake parts...

Also going to pull the struts off that car in the morning, maybe a different one depending on interchangability, got some axles too, i think if i got the bushings ill be good to go as far as that is concerned... I might just put the fuse in the fwd box and diagnose the awd after the weekend.

 

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16 hours ago, GeneralDisorder said:

It is perfectly fine to load them in the air. That's why I suggested it. We do it all the time with the car on the lift above our heads. 

GD

I missed your first post.. Front inner doj? Whats a doj? 

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  • 2 weeks later...

Unfortunately I cannot verify exactly what it was, but vibration had dissapeared after replacing Rear Shocks, Axles and Bearings, and before i replaced the front shocks. So... hopefully that helps someone. :)

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