The great LWFW NVH deal

So it appears that most if us, when we changed our flywheels over to single mass or lighter have experienced "the box of rocks" effect. Now I know the tendency is to blame the flywheel because that's what happened after you changed it out, seems fairly obvious.

 

However, my noise began as a slight rattle or vibration, and it stayed that way for many months, but when i moved and drove cross country, the problem exacerbated and its very loud. I took it to a place to check it out and they put it on the lift with a driver to put it in gear and it is not from the flywheel, but the center differential inside the transmission.

 

The bearings are wearing out, which I believe is happening to many of us. However, can we reverse the noise issue by reverting back to OEM clutch/flywheel and oem bushings?

 

Has anyone reverted back to OEM and had the problem ho away?

reverting back to OEM weight won't solve the vibration caused by the diff, but it will reduce some of the NVH caused by having a lwfw. Have you also checked stuff like the condition of the bushings/mounts? Wear of these items can cause different resonances

It's the transfer case bearings and/or gear back lash.

You've shifted the load on them.

 

There is a HUGE thread on NASIOC about this.

So a lwfw will wear these bearing out faster?

Or do some cars just have bad bearings?

Do you happen to have that link to Naisoc?

 

Given the observational evidence that most people complain about the issue following the installation of a LWFW, I am tending to believe that it is the problem, and therefore would suggest against installing these products, even though results vary. Some do not have issues at all, but do you want to risk it?

FWIW, I have had all the bearings replaced in my tranny more than a couple of times. The noise stays the same ever since the Spec LWFW was installed at 72,000 miles.

 

3rd and 4th gear sound like a bucket of rocks on decell going down a hill.

FWIW, I have had all the bearings replaced in my tranny more than a couple of times. The noise stays the same ever since the Spec LWFW was installed at 72,000 miles.

 

3rd and 4th gear sound like a bucket of rocks on decell going down a hill.

 

My 3rd and 4th are the worst as well... though 2nd was the worst until I swapped to the BAC5.2 cocktail. Since changing fluids my trans has gotten much quieter. The decel noise is still there, just not as bad as before.

 

I can't imagine it would be cheap to replace the bearings in the trans.. Is it worth it to swap the bearings or just start saving for a 6mt swap??

I never had the noise when I first installed my single mass flywheel, but within 3000 miles I started getting a loud whine from the trans. I replaced the output shaft bearings in the center diff, they were spalled and worn. I don't think the clutch had anything to do with it....there is a TSB from Subaru about revised bearings for greater durability. The new bearings have twice the number of rollers the original ones had. Super easy job,do it with the trans right in the car in about 2 hours.

So a lwfw will wear these bearing out faster?

 

Doubt it, my cars been making the noise for 3 years or so and there is no excess shavings etc when I drop the gearbox oil.

 

Do you happen to have that link to Naisoc?

 

http://forums.nasioc.com/forums/showthread.php?t=1097682

and

http://forums.nasioc.com/forums/showthread.php?t=1920210

and

http://forums.nasioc.com/forums/showthread.php?t=1922615 - which was a bent arm or something.

 

But there are alot more than just those 3 on the first 3 pages in the Transmission section.

OK so the answer appears to be the OEM fly and clutch makes the noise go away. That is testimony from 4 members on NAISOC who had the noise, and upon reverting back to stock, noise went away, I will be doing this soon, as I do not see the benefit of the LWFW over stock in the first place, at least not worth the hassle this has caused.

 

My setup was a 2007 WRX flywheel and matching exedy clutch kit.

 

All kinds of people trying to diagnose, I think replacing the clutch is cheaper than a tranny rebuild and sounds a whole lot cheaper too, worth a try.

My first LWFW install at around 30,000 miles (2007) did indeed introduce NVH. At 70,000 (2010) I replaced the clutch and upon reinstall, the problem was largely cured. The parts were the same - the difference was made by the installer. The first time I took it to a local Performance Shop specializing in Subaru. The second time I took it to a dealership but also all supporting parts were replaced, including throw-out bearing; tranny mounts were replaced with either new and/or STI / Group N part(s). Therefore, the quality of the install might also be due to new/improved parts not just a more experienced hand.

 

My setup consists of an ACT Heavy Duty Clutch and ACT LWFW for the 06-07 WRX

Interesting, however you still have some noise and vibration correct?

A true LWFW will almost always be accompanied by deceleration chatter. This is normal.

 

For OEM SMFW users there should be no decel chatter. Not unless it is very very cold and/or your gear oil needs a change (my experience).

 

Obviously bearing wear and internal component wear could/would also contribute to any noise.

I am planning to revert back to stock, complete OEM with extra-s gear oil. Sucks because it's so expensive but these cars hate anything you do to them, so I will remain stock all around with the exception of my catback. I am surprised I didn't get some kind of code for that on this car. Never had a car I loved and hated so much.

 

Thinking about selling soon if anyone is interested. Located in S. Florida

OEM WRX flywheel here, no decell noise what-so-ever.

OEM WRX flywheel here, no decell noise what-so-ever.

 

+1

 

OEM single mass flywheel and clutch setup has no noise on deceleration, while idling, or anything. That plus the Extra-S gear oil has my car running better than it did stock for sure.

Hmmm, this has me rethinking my setup. I got my hands on a LWFW, but I think I'm going to keep my OEM WRX and be happy. How much power is the matching OE clutch good for? I'm only at stage 1, but stage 2 is coming in the near future.

 

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....there is a TSB from Subaru about revised bearings for greater durability. The new bearings have twice the number of rollers the original ones had. Super easy job,do it with the trans right in the car in about 2 hours.

 

Link to the TSB. Worth it to have this knowledge and the revised P/Ns going forward.

Im interested in more info on this as well. I have replaced my center diff and rear output shaft and bearings 40k ago. Then new bearings (updated PN) 10k ago. Then new bearings last week. Again. I have been changing fluids very often (4 times in those 10k miles) with Andrewtech Cocktail. Before that it was extra-s. Now I have Ford 80-90 and will be switching to something else come race season.

TSB NUMBER: 03-68-12

DATE: 07/16/12

APPLICABILITY:

Legacy and Outback 2000-2009MY w/ 5MT

Forester 1999MY and Later w/ 5MT

Impreza (Including WRX) 1999MY and Later w/5MT

SUBJECT:

5MT Transfer Driven Gear Bearings

INTRODUCTION

This bulletin reviews a change to the part numbers used for the transfer driven gear bearings. These revised bearings are to be used to enhance durability. Changes to the tools required and supplemental procedures for the installation of these bearings are also covered.

COUNTERMEASURE IN PRODUCTION

 

SERVICE PROCEDURE / INFORMATION

After installing the new bearings on the transfer driven gear using the proper tools, apply 1g (.035oz.) of grease on the roller bearings as shown in the above photos. Install the gear assembly into the transfer case and rotate the shaft to spread the grease throughout the front bearing rollers evenly. Repeat the procedure for the rear bearing in the extension housing. Follow the remaining procedures as outlined in the applicable Service Manual.

Grease: Nichimoly N130 or Conoco-Phillips Multiplex Red #2 grease

 

 

 

http://www.alldatapro.com/images/blnk_spc.gif

+1

 

OEM single mass flywheel and clutch setup has no noise on deceleration, while idling, or anything. That plus the Extra-S gear oil has my car running better than it did stock for sure.

 

I have a WRX clutch set up, albeit the OEM flywheel with Exedy clutch kit and my noise it off the charts.

 

On the NAISOC site, those who switched back to OEM clutch all the way, found that it stopped the noise, even after driving with the noise for quite a while. I am thinking it is more of a harmonic issue than anything else.

I have a Spec LWFW and the NVH doesn't drive my up the wall :shrug:

 

It does make noise but I don't find it intrusive.

Just a note here on those transfer gear bearings. If you are having repeat failures the bearing preload is probably the culprit and needs to be recalculated.

Any page I've found with mention of Nichimoly N-130 is filled w/ Kanji characters I can't read.

 

 

There is no shortage of ConocoPhillips distributors, but it seems every one wants to sell you a case or more of this grease...

 

 

...except Fastenal!

 

https://www.fastenal.com/products/details/0411136