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Odd drivetrain noise. Not your classic CV

Posted: Mon Aug 18, 2008 12:28 am
by evm1024
Just did a few miles of a bumpy mountain road. Not even what I would call spirited driving....

The car is a 1994 Legacy wagon 4wd. Non-turbo.

I've got a noise or rather a set of noises that I cannot pin down. At first glance you would think bad CV and move forward but....

OK I'm getting a loud thumping as if something is hitting the undercarriage mostly when turning left. I also ger a more classic CV clack alack clack when turning left. But also when turning right I get a metallic scraping that becomes a ringing when turning right.

These are slow speed turns with a lot of turn.

No like sounds when going straight at up to freeway speeds or when going straight and pumping the accelerator.

I did pull the roght front wheel off and looked for any loose steering parts. Nothing obvious. I did not get far enough under the car to look st the drive shaft or its mountings.

I'm looking for thoughts/suggestions and anything that wouuld help.

Next step is to see about having a shop take a look at it and figuring ouut which CV replacements are worth it at a decent price.

Regards, Ethan

Posted: Mon Aug 18, 2008 2:30 am
by ericem
Im betting on the cv's. You say you don't see any broken boots? If there is no play I would narrow it down to the axles.

Posted: Mon Aug 18, 2008 3:00 am
by Legacy777
AT or MT?

Posted: Mon Aug 18, 2008 7:27 am
by evm1024
MT

Solved

Posted: Thu Aug 21, 2008 4:01 pm
by evm1024
It stopped raining enough for me to crawl all te way under the car to look it all over.

THe drive shaft has a bearing mounted in a frame that is mounted to the chassis before the shaft heads for the rear diff. This frame is bolted to the chassis with some rubber bushings. One of the bushings broke and the frame was able to move.

Sitting in the driveway it looked like it was OK but when driving the torque caused the frame to move striking both the chassis and what was left of the bushing. At slow speeds it thumped the bolt as the u joint turned thus sounding kinda like a CV going out.

During stronger torques it thumped back into place giving that noise.

And lastly it could get so far out of line in slow speed turns that the drive shaft contacted the protective housing just before the rear diff making the ringing sound.

So in many ways this is very nice in that an expensive worry becomes a few $ of bushings.

THanks to all, Ethan