Strange noise ??

scoobydo · #1 05-30-2012, 02:19 PM

Ok I hope if I throw this out there - I may get the answer so here goes ! (after all you guys are the knowledge !)
1992 SVX with good service history. 106K miles genuine.
After market alloys and tyres. All checked and AOK
JUST rebuilt rear diff - all AOK
JUST fitted NEW rear wheel bearings all AOK
Rear brakes and discs could be better (new ones very soon) but still serviceable so read AOK.

The above was done to try and hunt out a strange noise.......
0 - 40mph we get a whoom whoom whoom that appears to be in tandem with road speed (I wish I could record this so you could hear it !) Above that it is either lost with the sound of the overall speed or it goes - I am not sure which !
The sound would appear to come from the rear left wheel !!! (hence we did that bearing first- and it was done for me by a Subaru expert so has been correctly done)

We are now thinking centre prop bearing ??

And of course thats a pita to get to (new SS exhaust coming as the one currently on wont be able to go back on !!)
There was lift in the diff input (which is now fixed)
The Auto box appears to be fine and works as it should.
Anyone had this ?? or can suggest a possible?

Thanks !

icingdeath88 · #2 05-30-2012, 05:37 PM

Quote:

Originally Posted by scoobydo

Ok I hope if I throw this out there - I may get the answer so here goes ! (after all you guys are the knowledge !)
1992 SVX with good service history. 106K miles genuine.
After market alloys and tyres. All checked and AOK
JUST rebuilt rear diff - all AOK
JUST fitted NEW rear wheel bearings all AOK
Rear brakes and discs could be better (new ones very soon) but still serviceable so read AOK.

The above was done to try and hunt out a strange noise.......
0 - 40mph we get a whoom whoom whoom that appears to be in tandem with road speed (I wish I could record this so you could hear it !) Above that it is either lost with the sound of the overall speed or it goes - I am not sure which !
The sound would appear to come from the rear left wheel !!! (hence we did that bearing first- and it was done for me by a Subaru expert so has been correctly done)

We are now thinking centre prop bearing ??

And of course thats a pita to get to (new SS exhaust coming as the one currently on wont be able to go back on !!)
There was lift in the diff input (which is now fixed)
The Auto box appears to be fine and works as it should.
Anyone had this ?? or can suggest a possible?

Thanks !

Does it seem to become more pronounced with increased load? If so then look at driveshaft and axles.

If it speeds up proportionally to RPMs, then look at the engine stuff (mounts, misfires, etc.) If it speeds up proportionally to ground speed, then look at bearings, drivetrain, axles, wheel balance issues (hubs, rims, tires), or maybe diffs.

Do you feel it or do you hear it? You usually hear bearings and tires.
you often feel axles. Driveshaft I'm not entirely sure, but I'd guess you'd feel it at least a little.

Usually front axle symptoms are easier to narrow down, because they give more feedback, especially through the steering wheel.

I'd lean toward one of the rear axles being bad, or a bad driveshaft U-joint or center bearing.

aust92pearl · #3 05-30-2012, 07:05 PM

Quote:

Originally Posted by icingdeath88

Does it seem to become more pronounced with increased load? If so then look at driveshaft and axles.

If it speeds up proportionally to RPMs, then look at the engine stuff (mounts, misfires, etc.) If it speeds up proportionally to ground speed, then look at bearings, drivetrain, axles, wheel balance issues (hubs, rims, tires), or maybe diffs.

Do you feel it or do you hear it? You usually hear bearings and tires.
you often feel axles. Driveshaft I'm not entirely sure, but I'd guess you'd feel it at least a little.

Usually front axle symptoms are easier to narrow down, because they give more feedback, especially through the steering wheel.

I'd lean toward one of the rear axles being bad, or a bad driveshaft U-joint or center bearing.

my car has a similar noise as well , im fairly certain it is the drive shaft unis and possibly the centre bearing as well ,
but i can feel and hear a very loud and pretty violent vibration when turning right or left from a stop .
i originally though it was the left rear axle but when driving slowly there is also an audible ting ting ting noise , which is the unis grabbing and releasing on where they are worn (my old rwd corolla used to do the same thing i replaced the unis and it was fixed ), it also makes a loud ting when reverse is selected

my suggestion is get a drive shaft from a car with cheap and serviceable/replaceable unis (in aust holden commodore ones are cheap and plentiful

) and have those uni bits welded onto the svx shaft at a drive shaft shop
thats what i plan to do with my drive shaft im getting for 5 speed

andreoz · #4 03-14-2014, 04:18 AM

Quote:

Originally Posted by aust92pearl

my car has a similar noise as well , im fairly certain it is the drive shaft unis and possibly the centre bearing as well ,
but i can feel and hear a very loud and pretty violent vibration when turning right or left from a stop .
i originally though it was the left rear axle but when driving slowly there is also an audible ting ting ting noise , which is the unis grabbing and releasing on where they are worn (my old rwd corolla used to do the same thing i replaced the unis and it was fixed ), it also makes a loud ting when reverse is selected

my suggestion is get a drive shaft from a car with cheap and serviceable/replaceable unis (in aust holden commodore ones are cheap and plentiful

) and have those uni bits welded onto the svx shaft at a drive shaft shop
thats what i plan to do with my drive shaft im getting for 5 speed

Did you ever get a Holden drive shaft modified for the SVX???

major7venth · #5 04-02-2014, 03:24 PM

More pronounced sound from left or right sides? Or can't tell? Wheel balance, axles, drive line. Get it off the ground, run it,see if the sound is still there.

SVX_MY_BABY · #6 04-03-2014, 07:54 AM

First, I'm no expert.

I had a similar experience with an Audi A3. Mechanic and service manager were sure it was wheel bearings, but when the car was on the hoist the bearings checked out OK.

The problem was extreme cupping of the rear tires. Replacing them cured the problem.

An easy way to check for cupping is to drive over a dusty floor. When you lift the car you can then easily see the pattern of wear on the tire. No dust or less dust where the tire is cupped.

Also a random thought. Are your differential bushings good? Bad ones would allow transmission of a lot of diff noise.