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Old 08-29-2008, 12:35 PM   #31
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I've explained this problem so many times before... It's a harmonic vibration in the diff caused by the compression strokes of the engine when decellerating. It is loudest in 4th because it is a 1:1 ratio.

The solution is to get a clutch disk with the proper stiffness springs like a stock disk. If your clutch has springs, but you get this decelleration vibration, then the springs are the wrong stiffness. This means the springs are now damping vibrations that aren't there, and failing to damp the natural frequency of the driveline.
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Old 08-29-2008, 10:41 PM   #32
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Quote:
Originally Posted by Def View Post
I've explained this problem so many times before... It's a harmonic vibration in the diff caused by the compression strokes of the engine when decellerating. It is loudest in 4th because it is a 1:1 ratio.

The solution is to get a clutch disk with the proper stiffness springs like a stock disk. If your clutch has springs, but you get this decelleration vibration, then the springs are the wrong stiffness. This means the springs are now damping vibrations that aren't there, and failing to damp the natural frequency of the driveline.


Well the way your saying it, it only happens on decelleration. Mine is also upon acelleration too. If it's coming from the diff wouldn't the sound be coming from the rear of the car and not the transmission? (IDK just asking)

I had a spec stage 3 clutch with a shaved flywheel in my 95 with SR and didn't have this problem. This problem on my 90 has been there even through break in period of the exedy.
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Old 08-29-2008, 11:28 PM   #33
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I have this prob too. Never really thought much of it though.

Spec Stg 3, Spec billet flywheel, DSS steel 1 piece.
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Old 10-16-2008, 11:05 PM   #34
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interesting that I find this thread. I just installed a new 4 puck clutch with chromoly lighten flywheel. New pilot bearing and new TO bearing. I never had any noise before the install since I had a stock clutch kit. Now it does the same thing most poster here have.

No noise on acceleration but as soon as you decelerate around 3k rpms theres a humming vibrating noise heard behind the shifter and vibration is felt in the clutch pedal if you lightly step on it. Loudest on 3rd and 4th gear.

Im gonna have to check with the company I bought this Clutch kit from and check the specs.. If it is a bad clutch disc with the wrong spring Im gonna get it fixed for sure. Either my pressure plate is loose (i hope not I put blue loctite on the bolt and torqued it to 30lbs not sure if thats the correct torque spec) or my Clutch disc has the wrong spring specs.. maybe to hard?
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Old 10-16-2008, 11:08 PM   #35
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heres the spec for my clutch.

OUR OWN DESIGNED CLUTCH IS MADE WITH THE DRIFTER IN MIND! WE USE A HEAVY DUTY PRESSURE PLATE WITH OUR OWN UPGRADED DIAPHRAM TO INCREASE TORQUE SPECS. OUR CLUTCH KIT CAN HOLD UP TO 300 FT. LBS. OF TORQUE! WE USE A 4 PUCK CERAMIC SPRUNG DISK TO ENSURE AN IMPRESSIVE AMOUNT OF BITE WHEN YOU CLUTCH KICK TO INITIATE A DRIFT. ALTHOUGH OUR CLUTCH WORKS GREAT ON THE TRACK, YOU CAN ENJOY AN EASY PEDAL FEEL WHILE DRIVING ON THE STREETS!


HEAVY DUTY PRESSURE PLATE WITH UPGRADED DIAPHRAM
-HOLDS UP TO 300 FT. LBS. OF TORQUE
-PEDAL FEEL GREAT FOR DAILY DRIVING, ONLY 20% OVER STOCK FEEL

*4 PUCK CERAMIC SPRUNG DISK*
-WE USED A 4 PUCK DISK FOR IT'S AGGRESSIVE CHARACTERISTICS NEEDED FOR DRIFTING
-SPRUNG DISKS ARE MUCH SAFER FOR YOUR TRANSMISSION AND EASIER TO USE ON THE STREETS
-CERAMIC DISKS ARE FAR MORE SUPERIOR THAN AN ORGANIC DISK
-WE USE A SPECIAL PLATE COVER OVER THE SPRINGS TO ENSURE THE SPRINGS WILL NOT COME OUT DURING DRIFTING AND AGGRESSIVE DRIVING (AS WE'VE SEEN IN THE PAST)
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Old 10-17-2008, 01:03 PM   #36
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Quote:
Originally Posted by sdblackgloves View Post
interesting that I find this thread. I just installed a new 4 puck clutch with chromoly lighten flywheel. New pilot bearing and new TO bearing. I never had any noise before the install since I had a stock clutch kit. Now it does the same thing most poster here have.

No noise on acceleration but as soon as you decelerate around 3k rpms theres a humming vibrating noise heard behind the shifter and vibration is felt in the clutch pedal if you lightly step on it. Loudest on 3rd and 4th gear.

Im gonna have to check with the company I bought this Clutch kit from and check the specs.. If it is a bad clutch disc with the wrong spring Im gonna get it fixed for sure. Either my pressure plate is loose (i hope not I put blue loctite on the bolt and torqued it to 30lbs not sure if thats the correct torque spec) or my Clutch disc has the wrong spring specs.. maybe to hard?
That's harmonic vibration, the springs in your clutch disk are either too soft or too stiff.
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Old 10-17-2008, 06:16 PM   #37
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okay thanks for clearing that up.
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Old 03-23-2009, 02:34 PM   #38
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yet another bringing up an old post. Same issues, ACT 6-puck unsprung. Slightly different question: is it bad for the driveline? AKA, should I avoid compression braking in fourth gear because of this vibration? Or does the driveline really not give a shit about it?

Thanks!
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Old 04-17-2009, 02:48 AM   #39
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Old 04-17-2009, 05:22 AM   #40
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I kinda just skimmed through the previous posts but I have to say, why does everybody keep blaming the driveshaft? I didn't see any body say that swaping it solved the problem. If the driveshaft was imbalanced you would feel the vibration all the time at higher speeds in all gears since the speed of it is only directly proportional to the speed of the wheels. Stop wasting money on new drive shafts when you don't really need it.

Since this is only happening on decel we could probably narrow it to differential or old busings flexing the opposite way of accel.
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Old 01-20-2010, 07:00 AM   #41
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Just did my clutch swap and the same thing is happening...the 4th gear accel and decel humming noise....I hate it
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Old 06-20-2017, 11:49 AM   #42
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I feel really bad for bringing this topic up but has any of you found out what the problem was?

I have the EXACT same problem. The thing is, even though I had a new 6puck clutch installed recently, I don't recall having such issue soon after I got the car back.

It feels like its coming from the back of the car, maybe differential area. Unless its totally misleading.
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