Engine/Transmission noise on deceleration

matdav · Post by **matdav** » Thu Feb 14, 2008 7:03 pm

I've got a 1989 Legacy Wagon manual transmission which is making a noise on deceleration. Sounds kinda like the mudflap rubbing against the tyre.

It's most noticable if I'm doing about 90km/hr in 5th and I take foot off the gas.

But it also does the same thing in 4th at about 70km/hr.

So it's related engine revs/min rather than wheel speed. Around 3000-3200 seems the magic number.

If I put the clutch in it goes away straight away. It also goes away once I'm below the 3000 rpm mark, So I'm guessing transmission rather than wheel bearing or inner/outer driveshaft joints.

I do see the left outer driveshaft boot is torn and needs replacing. But my logic would tell me that it's not the issue.

Any ideas on how to diagnose the root cause???

Matt

AlpineRaven · Post by **AlpineRaven** » Thu Feb 14, 2008 8:18 pm

Have a look at this thread - showthread.php?t=8865

Have you lifted the liberty on a hoist or jacks recently or after the noise appeared?

I remembered that I had that noise in my 1st Liberty before it was written off and now I had this noise in my Lib wagon since I bought it more that 1 yr ago... now its better and it doesnt have these noises...
Cheers
AP

matdav · Post by **matdav** » Fri Feb 15, 2008 5:55 pm

Checked out the thread. I don't have a metal on metal clunk as such, more of a whine, like say the sound you'd get with a circular saw cutting through a bit of 4 x 2.

But I'll crawl under the car tomorrow and inspect anyway.

AlpineRaven · Post by **AlpineRaven** » Fri Feb 15, 2008 6:08 pm

Is it FWD or 4WD/AWD?
Cheers
AP

Suby Wan Kenobi · Post by **Suby Wan Kenobi** » Fri Feb 15, 2008 6:11 pm

Your harmonic balancer hasnt become loose? Or one of the cam pulley wheels have a bad bearing?

matdav · Post by **matdav** » Fri Feb 15, 2008 6:17 pm

4WD model.

Not 100% sure what harmonic balancer is. Does it have another name?

Doesn't sound like it's coming from the front of the engine (cam pulley). And only get it under engine braking. Never noticed it on acceleration or when I'm stationary and reving.

AlpineRaven · Post by **AlpineRaven** » Fri Feb 15, 2008 8:46 pm

It might sound like your centre diff is on its way out.... have you recently changed the gearbox & rear diff oil? (it wouldn't make much difference)
What you'll need to do is go under the car and inspect all joints, bushes and your drive train as well..

Harmonic Balancer is the main pulley on the crankshaft, it has rubber ring around it and they do wear out..

How many kms on the clock has it done?
Cheers
AP

matdav · Post by **matdav** » Sat Feb 16, 2008 6:27 am

235,175kms on the clock. So she's getting fairly long in the tooth. Whatever the issue is it doesn't sound easy/cheap to fix. I'll take it to the chaps at Subaru to get the low down. If they can tell me exactly what it is then I might be able to repair/replace it myself. Otherwise I'll have to just pretend not to notice the noise

Thanks
Matt

AlpineRaven · Post by **AlpineRaven** » Sun Feb 17, 2008 10:43 am

Hmm... centre diff isn't "easy fix" as it requires taking gearbox apart.
Have a look at obvious areas where its possible noise could be coming from like what I said above... if you cannot find the noise - then tell the Subaru mechanic or someone who knows Subarus to get 2nd opinion.
Cheers
AP

Suby Wan Kenobi · Post by **Suby Wan Kenobi** » Sun Feb 17, 2008 4:25 pm

235000kms isnt what i would call long in the tooth for a Suby, maybe tailshaft centre bearing?

matdav · Post by **matdav** » Sun Feb 17, 2008 5:33 pm

Thanks for the advice. Found another thread on another forum with same symptoms "5th and 4th gear 2500-3000 rpm i get a weird ass vibration. feels like im driving on the median rumble strip". It went on to mention the center diff also so at this stage is the prime suspect.
Haven't had a chance to get under to inspect areas suggested but I'll do that before I take it to Subaru.

Will let you know the outcome next week.