Bad clutch rattle After ACT

[mattg]

BTW, my stock disc and FW looked really good upon removal. The disc looked like it could go another 20k or so and the FW was nearly perfect. No hot spots. My TOB was pretty shot though, and the PP fingers had a circular wear pattern near the ends from the TOB.

 

This was at ~ 64k miles.

[94sportsedan]

Which indicates pretty well that the TOB is constantly spinning, causing it's inevitable failure prematurely! The slave cylinder has such a powerful spring in it that causes constant pressure on the clutch fork, applying the TOB always.

[Scooby2.5]

Well just installed my WRX flywheel, ACT streetdisc clutch kit and used the TSK3 TOB kit.

 

I have the same rattle/noise on deceleration. I agree with 94, that I havent noticed this while riding in a WRX so why do we get this with the WRX flywheel and ACT setup.

 

I dont think the TSK3 kit has anything to do with the noise we are hearing. That kit just make the bearing have a smooth place to ride and clips the bearing to the fork.

 

Other mods done to my car that may affect this are, group N tranny and motor mounts, and a lightweight crank pully.

 

Not really sure why we all have this.

 

It is a bit annoying but the clutch benefits will far outweigh the stock benefits especially at 350/373 stage 3

 

I killed the car when I first took off from the dealer who installed it, drove it home in some traffic about 35 miles. It never really has shuddered when letting it out. Feels stiff to push but I would think this would get better.

 

Man does it grab though. Cant wait to put the full 22lbs of boost to it.

 

How many miles do they say you need for break in before really getting after it?

[Guest]

My ACT HDSS clutch (6MT) got quieter over time, and softer to engage. Still grabs incredibly well. I think it has been getting quieter even recently at least till 3k miles (almost 4k miles on the clutch). At the begining the noise bothered me as hell, now I barely notice it.

 

Give it time.

[TSiWRX]

How many miles do they say you need for break in before really getting after it?

 

http://www.advancedclutch.com/technical/faqs.aspx

 

Eight questions down.

 

I use the old-school adage of 300-500 city-miles.

[Scooby2.5]

Thanks unclemat and TSI. I actually found that question on the ACT site after I posted.

[Scooby2.5]

Here is a thread on NASIOC about similar noise on the WRX. Early posts are from 01, but it gets up to 09 by the end. Long thread.

 

http://forums.nasioc.com/forums/showthread.php?t=103494

 

If you search WRX deceleration noise on NASIOC you will find many threads. Seems its a common problem on the WRX, and since we now have WRX clutch......

[TSiWRX]

^ Very interesting! Thanks!

[Scooby2.5]

Did a google search: 2006 subaru wrx transmission noise

 

Good read:

 

Subaru WRX Transmission - Gear Attack

 

Gear set solutions

By Scott Wills

 

 

The Subaru WRX has established its superiority with an affordable price tag and unforgettable all-around performance.

The WRX in stock trim can be a competitor almost anywhere it goes, whether it is rally or road racing; out of the box, this car disappoints many adversaries.

The five-speed transmission, however, is the topic of conversation for many enthusiasts on the street and many competitors at the track. The majority of the complaint list goes as follows:

Gear Set Symptoms

1) Hard launches break first gear

2) The car will not go back into first gear unless you come to a complete stop

3) Fifth gear is absolutely useless at the track

4) Constantly stuck between the top of first and the power in second

5) Transmission makes noise during decceleration

 

These aren't reflective of the opinions of the average WRX owner, but instead from those who push their WRXs to the very edge. Of course, as always, preventative maintenance is the name of the game for the WRX and its not-so-loved transmission.

Most of our testing was done with a few rally-prepped WRXs. Rallying is the ultimate test bed for any product because of its extreme conditions. A rule of thumb is, if it can stand up to rallying, it will stand up pretty much anywhere.

1) Hard launches break first gear

 

Most complaints come from those who have admitted to revving pretty high before dumping the clutch. The AWD cars are great for getting power to the ground, offering astounding amounts of traction.

When you modify the 2.0 turbo engine, it's easy to find a lot of torque and horsepower quickly, but remember the rest of the car needs to be addressed to handle the power gains.

The number one suggestion is to be aware of potential weaknesses and don't side step the clutch. It is very possible to launch hard with a little clutch finesse; however, be prepared to regularly maintain the clutch linings.

The other option is going with an after market gear set. Most of the aftermarket gear sets are way stronger than stock, but hard launches can destroy way more than just first gear...trust us.

2) The car will not go back into first gear unless you come to a complete stop

It always starts with a little synchro scratching going back to first gear. A new car is usually able to find first gear from 20 to 0 mph. Eventually, that speed lessens until all you get is an excruciating grinding noise unless you are at almost a complete stop.

This noise is very frustrating at the track, especially when the track has a lot of hairpins or very tight corners where first gear would be effective. First gear becomes useless as soon as you shift out of it until you come to a complete stop. The first thing to try is upgrading the transmission oil. The factory Subaru oil is not bad, but there are some very advanced lubricants on the market that can help with this problem.

We stumbled into the ultimate Subaru tranny oil info. We all know the basis for R&D on the WRX is rallying, so what does the World Rally Championship Subaru team run in their cars? Neo Synthetic lubricants, which are manufactured and distributed here in the United States.

We tried some Neo gear oil and eliminated a lot of the issues with the synchros going into first and fourth. The car was once again able to find first gear at around 20 mph. If you have been experiencing grinding issues, there's a chance that nothing short of replacing parts can remedy the problems.

3) Fifth gear is absolutely useless at the track

A WRX with stock tires will do a little more than 120 mph in fourth gear. As best as we can tell, fifth gear is just for highway cruising and fuel economy. There aren't many venues for club racing that warrant or have the track for speeds of more than 120 mph.

Best option here is an aftermarket gear set that has ratios more inclined to keep the WRX in its powerband throughout every gear. A close ratio system is ideal.

4) Constantly stuck between the top of first and the power in second

The thing on every WRX owner's mind is the six-speed STi transmission. Yes, this is definitely the best option for some in-between ratios; however, the expense of the transplant is not cost-effective for some of the grassroots racers, nor will it be legal under some series' rules, which require a standard transmission setup.

Changing the gear ratio in the factory box is a very effective way to go about it. There are gear sets available that help to make first gear usable by making it just a little taller, and second gear a little shorter.

5) Transmission makes noise during deceleration

This is a common problem, but technically not a problem at all. It's just a matter of inconsistent factory backlash in the ring-and-pinion gear. Some models do it more than others.

The Subaru dealership can fix the problem, but not with performance in mind. The dealership will replace the 27 -pound flywheel with a heavier model to keep the gearbox loaded, thus eliminating a decelerating noise.

Going the opposite direction with the flywheel weight will not get rid of the noise, nor will it increase it. The lighter flywheel will be noticeable in how quickly the car finds its powerband. Suggestion: Get over the noise. It's not a big deal, and certainly not worth compromising power.

In our research we have come up with a gear set that can take care of most of the rally and road racers complaints. Gimmie Gears & Accessories offers a "Sport" ratio that is most effective across the board.

The taller first gear of the sport ratio tends to fill the first to second void, and when you shift through the rest of the gears, you have a slightly shorter than stock rpm drop (approximately 750 rpm per gear), keeping the WRX in its desired powerband. The gear set has fewer, yet bigger and stronger teeth, offering the necessary strength for even heavily modified WRXs.

We contacted GT Motorsports, in Rancho Cucamonga, Calif., about handling the gear install for us. Follow along as we see exactly what it takes to do a performance upgrade inside the 2002 WRX five-speed gearbox.

[SSpeed]

Ugh, I remember the ACT clutch spring rattle from the days of my Talon and ACT 2600. I have to replace the Legacy clutch soon and don't want this again. It's primarily the clutch springs causing the rattle and not the flywheel correct? I love light flywheels and grabby clutches, I HATE clutch chatter.

[Breeze91]

I have an exedy stage 1 and when I bought it the guy showed me the three different types of springs designed to work well in the hub of the clutch to reduce all noise and give equivalent to oem feel. Great I thought. But mine rattles too, not enough to hear from inside the car but enough for me to notice in an enclosed space.

 

Technically clutch chatter is equivalent to when you have bad front disks, the clutch is grabby in spots and difficult to engage cleanly and makes a noise doing it as it loads up the input shaft unevenly.

 

My clutch and that of most of the posters here is smooth as silk in engagement with great feel. What we get is an annoying rattle with the car in or out of gear not chatter which usually refers to the action of the clutch as it engages.

 

Some get it on decelleration

Some get it between about 1000-2500revs in the lower gears and at idle

Some get it every gear

 

It is pretty clear it is harmonics, but is it the TOB rubbing on the clutch and passing the rattle through the clutch fork or the TOB itself?

Is it the springs in the clutch disk?

Is it that the FW isn't balanced as well as oem

Is it the backlash in the FD and play in the input shaft

 

Whatever it is, the bigass dual mass seems to have enough mass that it modulates these harmonics to stop it happening. Kinda overkill but it works. Question is what can we do to quieten these down? Better question - how do we do it without splitting the engine/trans again? For instance we all want a solution akin to putting a rubber washer between the slave cylinder and the clutch fork.

 

I notice jeeps had the same problem with a rattle from the clutch and exedy released a technical fix which included an extra absorber around the clutch hub.

 

Now that I know everybody's cars do this I am happy that an input shaft bearing has not collapsed and a 2012 like amegedon is not going to befall my car. But the vain individual I am I don't like people looking over at my car as I gently take off from the lights and think geez - nice car but what about that rattle (of course no one is thinking that - they are usually wondering what they are going to have for lunch, what they need to get at the shops or who they might be screwing that evening).

 

So, armed with the knowledge that people find their sex life more interesting than any noises coming out of my car I will get over it and enjoy the benefits of the new clutch and the quirky little noises that remind me that my car is a little different to the rest and how rubbish my old clutch was.

[soobnoob]

Gear rattle I'd bet.

This guy has it right. It's gear rattle, or gear lash noise which the stock dual-mass flywheel helps prevent by dampening the pulses coming from the motor so the gears don't couple and decouple abrubtly which causes the grinding noise.

 

 

Clutch chatter is felt as a shudder that shakes the entire vehicle.

[trackhore]

What about the LGT's that no longer use the dual mass flywheel from the factory, 07+ I believe.

[Scooby2.5]

I disagree that it is gear rattle, and here is why I think this.

 

If you ride in a 2006 WRX, you DO NOT hear this deceleration rattle.

 

The ONLY time I have heard it is when someone changes to a different clutch.

 

I agree the dual mass flywheel cuts down on gear noise and so on but if the flywheel were the cause of what we are hearing in our legacies you would hear it in the WRX as well. Frankly I have not heard it when in other club members imprezas.

 

So the only logical conclusion, is it has something to do with the aftermarket clutch disc or pressure plate.

 

If the tranny is the same as the WRX, and the flywheel is the same, the only other variable it could be is the clutch.

 

I have driven mine for a number of months now.....

 

I LOVE the clutch, how it feels, how it takes off etc. and I havent killed it taking off since installing it. The old clutch with the drive by wire was the making of the hardest manual I have ever driven. With the new clutch I havent had any drivability problems at all.

 

With that said I HATE the rattle on deceleration.

 

Its annoying as heck, and I am really curious what ACT would say about this.

[Scooby2.5]

What about the LGT's that no longer use the dual mass flywheel from the factory, 07+ I believe.

 

or the WRX like I just posted.

[soobnoob]

I disagree that it is gear rattle, and here is why I think this.

 

If you ride in a 2006 WRX, you DO NOT hear this deceleration rattle.

 

The ONLY time I have heard it is when someone changes to a different clutch.

 

I agree the dual mass flywheel cuts down on gear noise and so on but if the flywheel were the cause of what we are hearing in our legacies you would hear it in the WRX as well. Frankly I have not heard it when in other club members imprezas.

 

So the only logical conclusion, is it has something to do with the aftermarket clutch disc or pressure plate.

 

If the tranny is the same as the WRX, and the flywheel is the same, the only other variable it could be is the clutch.

 

I have driven mine for a number of months now.....

 

I LOVE the clutch, how it feels, how it takes off etc. and I havent killed it taking off since installing it. The old clutch with the drive by wire was the making of the hardest manual I have ever driven. With the new clutch I havent had any drivability problems at all.

 

With that said I HATE the rattle on deceleration.

 

Its annoying as heck, and I am really curious what ACT would say about this.

A sprung clutch disk can act somewhat like a dual-mass flywheel in preventing gear lash noise. Are the OEM WRX and/or 07+ LGT clutch disks sprung? Secondly, unless the LGT and WRX 5-speeds use identical gears 1-5 it's not an apple to apples comparison.

 

http://www.uucmotorwerks.com/flywheel/gear_rattle.htm

[Breeze91]

All the replacement clutches in a stage 1/2 variety come with sprung disks. In fact they are the WRX clutch. It is also important to note that the factory sachs DMF clutch disc was also sprung unlike the BMW solid centre disks.

 

The gears between the WRX and legacy are not the same and in fact even legacies that have different final drives all do it (4.11 vs 4.44).

 

Would be interesting to jack one wheel of a legacy up and one wheel of a WRX up and check the relative difference in backlash (ie how much the wheel will turn in each direction until it meets resistance). I don't think it would be very different.

 

I agree that there has to be some solution if the cars which are practically the same don't do it (ie 07+).

[soobnoob]

Are the 07+ gears identical to the 05-06 gears? All of the impossibilites must be eliminated before a sweeping conclusion that goes against a myriad of evidence in other applications can be drawn.

 

 

In any case, the cause of the gear rattle is the only thing that is up for debate. The fact that it is gear rattle as opposed to true clutch chatter (a shudder felt throughout the vehicle while slipping the clutch) is not. We are essentially in agreement in that the clutch isn't the cause of this since the same clutches in different applications don't cause noise.

[TravisS]

Flywheel type aside, weight has a ton to do with it too.

Do those who swap in a 06 WRX flywheel have the chatter? It's quite a bit heavier then the ACT flywheel, which most definitely has the chatter.

[SSpeed]

Are the 07+ gears identical to the 05-06 gears? All of the impossibilites must be eliminated before a sweeping conclusion that goes against a myriad of evidence in other applications can be drawn.

 

 

In any case, the cause of the gear rattle is the only thing that is up for debate. The fact that it is gear rattle as opposed to true clutch chatter (a shudder felt throughout the vehicle while slipping the clutch) is not. We are essentially in agreement in that the clutch isn't the cause of this since the same clutches in different applications don't cause noise.

 

I'm confused by this statement... clutch chatter can definitely be spring chattering on decel... are you speaking more of the gear whine on decel? Gear whine and decel chatter are much different....

 

Once I get the engine back in our other Subaru I'm going to do the Legacy clutch. Southbend clutch and ACT flywheel. I'll see if there is chatter like when I had the ACT clutch. Southbend is guaranteed not to chatter.

[soobnoob]

I'm confused by this statement... clutch chatter can definitely be spring chattering on decel... are you speaking more of the gear whine on decel? Gear whine and decel chatter are much different....

I am speaking specifically about gear rattle that occurs with the clutch completely out in a certain RPM range upon slight acceleration or deceleration. I have never heard of "spring chatter". Are you referring to the clutch disk springs?

 

Southbend is guaranteed not to chatter.

Again, we are arguing semantics but I think the difference is important enough to mention. Clutch chatter as it has been classically defined is a shudder felt throughout the vehicle while slipping the clutch caused by the disk catching the flywheel, skipping off slightly, catching again, etc. This goes away when the clutch is completely engaged. This rattle that people are hearing is not clutch chatter.

[SSpeed]

Hmm, I don't know.. I honestly can't say I know enough to even specify... I just know on my last car I had terrible decel chatter... replaced the clutch, left the flywheel the same, and it was gone... the gear whine was still there, but the decel chatter disappeared... then I went to an ACT 2600 clutch and the decel chatter was back with a vengeance...

 

By decel chatter I mean letting off the gas to where the car is just "coasting", chatter like crazy, touch the gas just a little bit and it disappears...

[94sportsedan]

After I installed my act clutch/ WRX flywheel the decel chatter sounds like the transmission was ready to grenade went coasting off the gas anything above 35mph. Took out the Group N trans mount and re-installed the floppy flimsy stock rubber mount and all is quiet. For a daily driver I'll put up with a bobbing shifter then the roar of drivetrain decel noise!

[SBT]

^ I was just about to ask whether those of you with this "noise," whatever it is, also have uprated/hardened bushings, mounts, etc., on your transmissions and/or engines.

 

I know on my 98 LGT, when I upgraded to Group N tranny and engine mount bushings, I picked up noticeable NVH at idle (clutch-in &/or clutch-out in neutral) and while driving accelerating/cruising/decelerating.

[eL GaTo]

It's gear noise. I was with the mechanic when he was poking around with the "stethoscope" and the noise was more pronounced at the tranny housing.

 

check out this thread:

 

http://legacygt.com/forums/showthread.php/act-hd-perf-street-tsk3-126428.html?t=126428