Growling/Clunking noise in rear while accelerating hard in 1st or 2nd ??

[moviemadness]

who here has that sound and is 100% ABSOLUTELY STOCK?

 

with ABSOLUTELY NOTHING MODIFIED EVER.

 

not like.. "i'm bone stock.... except for TDC stg1.."

or .. "stock.. with drivetrain mods, turbo upgrade meth injection, 500whp.. but.. somewhat stock."

 

also, it has nothing to do with the stock tranny mount. I have Cobb's and it still makes that sound

[Turninconcepts]

I tried to get a few pictures of the bushings before my camera died.

 

The first pic shows the front bushings

 

[ATTACH]33462[/ATTACH]

 

The second pic was my attempt at taking a picture of the rear bushings. you can barely see them behind the rear swaybar.

 

[ATTACH]33463[/ATTACH]

 

The diagram in the post above is right on

 

Very Very interesting. Your bushing in that location is different than what's on the outback. I need to get one of the local guys to come over so we can try something.

 

OR - and this serious - if someone wants to try my idea I will send them the parts for free. there are a few conditions -

 

1) You be technically competant

2) You do the work quickly - sorry, gotta complain here for a bit. I HATE when someone begs me to let them test a part and when I send them the part I get "oh, dude. I'm at school and won't be home for 3 weeks." Here's the deal with testing - you test so we can release. Sometimes there's several thousand dollars worth of stuff sitting here waiting for your test results.

3) You're willing to give it a shot.

 

Here's my theory - I agree with the natural harmonic thinking. I think you're just hitting something that's setting up a resonation.

 

Here's the experiment - change a set of the bushings to a different stiffness. Could this make it worse? Maybe. Could it make it better? Maybe. We won't know for sure until we try. Now, here's the good part - that spot on the Outback will fit our GD impreza rear diff bushings perfectly. Not many people know this, and they aren't changed on the wife's outback for the same reason I have a stack of parts in the corner for my own car. I'm HOPING nothing changed in that mount except the bushing. If the dimension are the same then we should be able to pop ours in pretty easy.

[NewScooby]

I am willing to attempt the install, and capable. I will have them installed or attempted to install within 7 days of receiving them.

 

My concern is that the weather is warming up where I live in Central Illinois, and the growl definately goes away when the weather is above freezing.

 

I will PM you my info, Well PM is giving me a forbidden warning for some reason. I will give you a call tommorrow from work, and I sent you an email via your website.

Thanks,

Brian

[jawwadh]

glad to see this thread is getting somewhere.. clint is the MAN!

[boostsr20]

who here has that sound and is 100% ABSOLUTELY STOCK?

 

with ABSOLUTELY NOTHING MODIFIED EVER.

 

not like.. "i'm bone stock.... except for TDC stg1.."

or .. "stock.. with drivetrain mods, turbo upgrade meth injection, 500whp.. but.. somewhat stock."

 

also, it has nothing to do with the stock tranny mount. I have Cobb's and it still makes that sound

 

He's not talking about the tranny mount.

[trabbic]

Very Very interesting. Your bushing in that location is different than what's on the outback. I need to get one of the local guys to come over so we can try something.

 

OR - and this serious - if someone wants to try my idea I will send them the parts for free. there are a few conditions -

 

1) You be technically competant

2) You do the work quickly - sorry, gotta complain here for a bit. I HATE when someone begs me to let them test a part and when I send them the part I get "oh, dude. I'm at school and won't be home for 3 weeks." Here's the deal with testing - you test so we can release. Sometimes there's several thousand dollars worth of stuff sitting here waiting for your test results.

3) You're willing to give it a shot.

 

Here's my theory - I agree with the natural harmonic thinking. I think you're just hitting something that's setting up a resonation.

 

Here's the experiment - change a set of the bushings to a different stiffness. Could this make it worse? Maybe. Could it make it better? Maybe. We won't know for sure until we try. Now, here's the good part - that spot on the Outback will fit our GD impreza rear diff bushings perfectly. Not many people know this, and they aren't changed on the wife's outback for the same reason I have a stack of parts in the corner for my own car. I'm HOPING nothing changed in that mount except the bushing. If the dimension are the same then we should be able to pop ours in pretty easy.

 

Thanks for tackling this, hopefully we can find a solution...

[HansGT]

If we can get this resolved before it warms up, that would be great. If not, we may have to have our friends in the north to help (Canada).

[mccorry]

Way to go, guys.... please keep us posted!

[Nighthawk CL9]

here in chicago next week is going to be in the 50-60 so i will try to see how the noise is either stopping, or going away after heat buildup. the only think that confuses the hell out of me is the weather change. if the noise was constant at all temps i would assume something was rubbing, or endlinks were hitting.

[Turninconcepts]

I am willing to attempt the install, and capable. I will have them installed or attempted to install within 7 days of receiving them.

 

My concern is that the weather is warming up where I live in Central Illinois, and the growl definately goes away when the weather is above freezing.

 

I will PM you my info, Well PM is giving me a forbidden warning for some reason. I will give you a call tommorrow from work, and I sent you an email via your website.

Thanks,

Brian

 

Parts are on the way.

[TRS]

I was under the car last night, had the exhaust off and was poking around the rear dif just to see what I could see. I discovered that there was quite a bit of play in my passenger side CV joint on the dif end of the axle. It was enough that when I grabbed the axle and pushed and pulled on it I could feel and hear it clunking. The other side only had a small amount of play.

 

Source of the noise on hard acceleration? Even if it isn't I still need to have it looked at.

 

Anybody else feel like grabbing their axle and checking out the joint?

[NewScooby]

Parts are on the way.

 

Good Deal

 

Any special tools needed for the job?

Also, I was thinking of soaking the bolts and bushings with PB Blaster tommorrow to aid in getting them out. Think its needed?

[trabbic]

Good Deal

 

Any special tools needed for the job?

Also, I was thinking of soaking the bolts and bushings with PB Blaster tomorrow to aid in getting them out. Think its needed?

 

I am not sure exactly what has to be removed, but PB Blaster will not hurt anything, so spray away.

 

Thanks for doing this, report back so we know how much it helps.

 

[Turninconcepts]

Good Deal

 

Any special tools needed for the job?

Also, I was thinking of soaking the bolts and bushings with PB Blaster tommorrow to aid in getting them out. Think its needed?

 

Soak the bolts with PB. I'm going to meet up with a local LGT this weekend. I'll be able to tell in less than a minute if our bushings will fit. I'm also going to try and get a ride and listen for this growl.

 

You know, you could always use the excuse we did at GEAE when an engine made a growl when starting up, "That's just the sound or power, baby!"

[mccorry]

Well... I was crawling around under the car today and found what I believe is the source of our noises...

 

The rear prop shaft... between the tranny and the rear differential...... is a two piece unit with a carrier bearing / bushing assembly housed in a rubber doughnut mount. The factory coating on this rubber doughnut was all flaked and coming off... like if you hit a painted rubber bushing hard.... the bushing flexes... but the paint doesn't. Same thing here. The paint was all cracked and peeling off. If I grabbed the prop shaft... I could move it 1/16" back and forth in the carrier assembly... there is that much slop.

 

My money is on that bushing getting cold and hard... thereby transfering the driveshaft vibration up through the floorpan.

 

I'll attach a drawing of the unit I'm talking about....

 

http://img242.imageshack.us/img242/4948/propshaftro4.th.jpg

 

Thoughts?

[trabbic]

"That's just the sound or power, baby!"

 

 

That's what I try to tell my fiancee!!!!

[trabbic]

Well... I was crawling around under the car today and found what I believe is the source of our noises...

 

The rear prop shaft... between the tranny and the rear differential...... is a two piece unit with a carrier bearing / bushing assembly housed in a rubber doughnut mount. The factory coating on this rubber doughnut was all flaked and coming off... like if you hit a painted rubber bushing hard.... the bushing flexes... but the paint doesn't. Same thing here. The paint was all cracked and peeling off. If I grabbed the prop shaft... I could move it 1/16" back and forth in the carrier assembly... there is that much slop.

 

My money is on that bushing getting cold and hard... thereby transfering the driveshaft vibration up through the floorpan.

 

I'll attach a drawing of the unit I'm talking about....

Thoughts?

 

There was some discussion about this being the cause of the deep vibration at about 2500-3000 rpm when at Stage 2, if I am thinking of the same part. this happened under full throttle at a higher gear. Pltek discussed making a part to fix this. I think it is different, because the "growling" can still be at higher rpm.

 

I think the problem we are having is farther back, at the differential. Tonight making a HARD right turn under power, I only got the sound when the rear end stopped sliding and planted. that says to me it is farther back. Remember it is more pronounced, when we have passengers in the back seats.

[Turninconcepts]

That carrier is bearing is common across all the scoobies. If that was the case then they would all have this sound, and they would have had it for a long time.

 

I believe perrin or beatrush make replacement bushings for there.

 

A good way to test the theory is to just put a washer under the head of the bolt to preload the bushing more. It may not eliminate the sound, but if that is the cause then it will move it somewhere else in the revband.

[wy4tt]

Haven't read all the threads...but it isn't just an issue of how the gears are cut, is it? 1st and 2nd being more straight cut gears and therefore more whine?

[mccorry]

No... this is a growl and vibration from the rear of the car.... not normal at all.

Kinda feels like you're driving over little rumble strips at speed.

[fweasel]

Haven't read all the threads...but it isn't just an issue of how the gears are cut, is it? 1st and 2nd being more straight cut gears and therefore more whine?

Read all the posts. I had to post, because you reminded me of Walter screaming at Donny in the bowling alley making reference to a 4 year old child walking in to the middle of a movie. Hijack --off--

[SeeeeeYa]

No... this is a growl and vibration from the rear of the car.... not normal at all.

Kinda feels like you're driving over little rumble strips at speed.

 

Someone, ANYONE!, Please find out what this is and what can be done about it.

 

Out of all the issues on these forums, or any issues on ANY OTHER forum, this remains the most perplexingly unanswered.

 

I'm sure this noise was not there in the beginning for me, even when cold, even when power brakeing. But far too many brake torqueing events later it is ever present. In my opinion, it is not a single source problem.

 

Recently I was made aware of the fragility of our LCA bushings, and inspection does, indeed, find mine ripped. Whatever materials were used in that bushing likely was used in other bushings, with similar longterm results. Certainly, the driveshaft assembly's bushing must be part of the problem, but likely the total picture is a combination of more than that.

 

Unless I am not up-to-date, I know of no current replacements for some of those bushings I suspect, definitively. Perhaps turninconcepts can step up and choose to do a project car themselves. To make their efforts profitable, however, we would need some sort of commitment from enough members. I, for one, subscribe to whatever group buy might evolve from this theoretical group buy solution.

[Vimy101]

^ My interest in this problem comes from my interest in long term maintenance issues that this bushing problem may pose. Members with modded engines may have accelerated a wear and tear issue whose solution may eventually benefit LGT owners.

[Turninconcepts]

Looks very much like our bushings will fit with a little bit longer crush tube. This is from a quick "slide under the car glance."

 

We're gonna pull the piece this week sometime, and try it out.

[mccorry]

I just did a Stg. 2 install on a buddies car tonight...

 

Before... STi Pinks.... stock tune ... no growl.

After ... STi pinks.... Cobb Stg. 2 ... Growls like a @#$?%#@$.