Does it get quiet when the clutch pedal depressed and the trans in gear? If yes, clutch isn't releasing all the way. If no, then the rattle is being caused by something else.
ZF6 Rattle
Thread Starter
Instructor
Joined: May 2005
Posts: 193
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From: West Islip NY
ZF6 Rattle
been reading up on the common rattle the 6spd makes when using
a single mass flywheel, keeping reading that it should go away when clutch pulled in? mine doesnt. no change at all in or out. works great, no problems, just real noisy. normal or not?
a single mass flywheel, keeping reading that it should go away when clutch pulled in? mine doesnt. no change at all in or out. works great, no problems, just real noisy. normal or not?
Le Mans Master
Joined: Aug 2015
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From: St. Charles MO
FWIW, mine gets pretty quiet with the clutch in. And that's with a single-mass flywheel that weighs around 12lbs. I assume that's because the input shaft for the transmission stops turning? It's pretty damn loud with my foot off the clutch pedal. I wonder if your clutch is slightly dragging so that the input shaft keeps turning?
Melting Slicks
Joined: Jan 2008
Posts: 2,054
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From: AZ
FWIW, mine gets pretty quiet with the clutch in. And that's with a single-mass flywheel that weighs around 12lbs. I assume that's because the input shaft for the transmission stops turning? It's pretty damn loud with my foot off the clutch pedal. I wonder if your clutch is slightly dragging so that the input shaft keeps turning?
Team Owner
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From: Park City Utah
Le Mans Master
Joined: Aug 2015
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From: St. Charles MO
Good point. So he can put it in gear, depress the clutch to the floor, then move it to neutral. If it makes more noise in neutral, then the clutch is dragging. As whalepirot noted, if the clutch is dragging it will wear the syncros with every shift. It should make it harder to shift cleanly as well, but if the dragging is light then the syncros may be overpowering it (they are like clutches, too).
Race Director
Joined: Sep 2001
Posts: 14,682
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From: NEwhere Ohio
Quiet transmission here with 12 lb fidanza lightweight alum flywheel.
Sprung hub spec stage 3+ clutch
Properly shimmd blue tag 'remanufactured' transmission. (Ie. Zf doc thicker countershaft shim installed)z
Tiny bit of light rapping at idle if you let the clutch pedal up and its in neutral - but who drives like that anyways? Lol.
Totally silent under all other driving situations
Sprung hub spec stage 3+ clutch
Properly shimmd blue tag 'remanufactured' transmission. (Ie. Zf doc thicker countershaft shim installed)z
Tiny bit of light rapping at idle if you let the clutch pedal up and its in neutral - but who drives like that anyways? Lol.
Totally silent under all other driving situations
Thread Starter
Instructor
Joined: May 2005
Posts: 193
Likes: 8
From: West Islip NY
Im pretty sure it rattles in gear too,but ill check tomorrow, what needs to be done if clutch is hanging up as you suggest it may be?
Im not even sure it has a single mass in it but previous owner said it has a brand new clutch in it so since dual mass ain't available im assuming
Its a single mass.
Im not even sure it has a single mass in it but previous owner said it has a brand new clutch in it so since dual mass ain't available im assuming
Its a single mass.
Race Director
Joined: Sep 2001
Posts: 14,682
Likes: 753
From: NEwhere Ohio
Im pretty sure it rattles in gear too,but ill check tomorrow, what needs to be done if clutch is hanging up as you suggest it may be?
Im not even sure it has a single mass in it but previous owner said it has a brand new clutch in it so since dual mass ain't available im assuming
Its a single mass.
Im not even sure it has a single mass in it but previous owner said it has a brand new clutch in it so since dual mass ain't available im assuming
Its a single mass.
Its might understanding it can be quite noisy if you dont put in a sprung hub clutch when replacing the dual mass with a lighter weight single mass flywheel
Probably some nasty driveability issues too.
Last edited by dizwiz24; Oct 17, 2015 at 07:07 PM.
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Team Owner
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From: Park City Utah
If you confirm this, then the problem is not a "ZF6 rattle". it would more likely be an exhaust heat shield, the dual mass FW, failed (if it has one), or something else rattling.
I wouldn't assume that. Most clutch replacements w/a DM flywheel involve scotch brite'ing the FW and reusing it.
I wouldn't assume that. Most clutch replacements w/a DM flywheel involve scotch brite'ing the FW and reusing it.
Thread Starter
Instructor
Joined: May 2005
Posts: 193
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From: West Islip NY
well i drove the car for an hour and for the first time it doesnt make a sound,cant make this stuff up. only thing different today is that its 40 deg out,but car was fully warmed up. anyway as tom400 said I guess i shouldnt assume i have a single mass as previous owner may not have swapped flywheel.
Thread Starter
Instructor
Joined: May 2005
Posts: 193
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From: West Islip NY
Le Mans Master
Joined: Aug 2015
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From: St. Charles MO
I am thinking that it does. Perhaps the clutch is so close to not dragging when it's warm that when it's cold it everything contracts just enough to make it not drag. Or maybe when it was cold the transmission fluid was higher enough viscosity that the very slight drag of the clutch couldn't overcome it. Either way, I think if your clutch is dragging it is very slight, because you haven't mentioned any problems shifting. However, as previously noted by someone else, it is worth checking and fixing because it will increase the wear of the syncros and make shifting fast more difficult. Does the clutch engage near the bottom of the pedal travel?
Team Owner
Joined: Aug 2004
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From: Park City Utah
The back lash, or clearance between the gears in a ZF6 is rather large - more than in other transmissions. Also, the gears in a ZF6 are big and heavy...again, more so than in other transmissions.
SO, the "ZF6 Rattle" is the noise created WHEN, the car is idling in neutral, BY the input shaft gear teeth whacking back and forth against the countershaft gear teeh as the crank accelerates and decelerates, several times per revolution...and the countershaft does not "want to".
NOW...the OP says that his car does this in gear. If the car is stopped, trans in first gear, what are the gears doing? They are doing nothing. They are stationary, along w/everything else, from the clutch disk, the the axle nuts. No way they can be causing a rattle, whether the clutch is dragging or not.
His rattle is caused by something else.
.
Last edited by Tom400CFI; Oct 22, 2015 at 07:22 PM.
Le Mans Master
Joined: Aug 2015
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From: St. Charles MO
NOW...the OP says that his car does this in gear. If the car is stopped, trans in first gear, what are the gears doing? They are doing nothing. They are stationary, along w/everything else, from the clutch disk, the the axle nuts. No way they can be causing a rattle, whether the clutch is dragging or not.
His rattle is caused by something else.
His rattle is caused by something else.
Thread Starter
Instructor
Joined: May 2005
Posts: 193
Likes: 8
From: West Islip NY
No. "ZF6 Rattle", is caused by the acceleration and deceleration of the input shaft that occurs w/every 90* rotation of the crank shaft. As a piston goes up on compression, the crank decelerates...that is immediately followed by a power stroke, which accelerates the crank, which is immediately followed by another compression stroke. Make sense?
The back lash, or clearance between the gears in a ZF6 is rather large - more than in other transmissions. Also, the gears in a ZF6 are big and heavy...again, more so than in other transmissions.
SO, the "ZF6 Rattle" is the noise created WHEN, the car is idling in neutral, BY the input shaft gear teeth whacking back and forth against the countershaft gear teeh as the crank accelerates and decelerates, several times per revolution...and the countershaft does not "want to".
NOW...the OP says that his car does this in gear. If the car is stopped, trans in first gear, what are the gears doing? They are doing nothing. They are stationary, along w/everything else, from the clutch disk, the the axle nuts. No way they can be causing a rattle, whether the clutch is dragging or not.
His rattle is caused by something else.
.
The back lash, or clearance between the gears in a ZF6 is rather large - more than in other transmissions. Also, the gears in a ZF6 are big and heavy...again, more so than in other transmissions.
SO, the "ZF6 Rattle" is the noise created WHEN, the car is idling in neutral, BY the input shaft gear teeth whacking back and forth against the countershaft gear teeh as the crank accelerates and decelerates, several times per revolution...and the countershaft does not "want to".
NOW...the OP says that his car does this in gear. If the car is stopped, trans in first gear, what are the gears doing? They are doing nothing. They are stationary, along w/everything else, from the clutch disk, the the axle nuts. No way they can be causing a rattle, whether the clutch is dragging or not.
His rattle is caused by something else.
.
Le Mans Master
Joined: Aug 2015
Posts: 6,119
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From: St. Charles MO
FWIW, my single-mass-equipped ZF6 is quite noisy when under heavy load at low rpms. I think that's par for the course. Back in the day, I had an 89 Mustang LX that did the same thing (but much quieter) even in completely stock form. And I've driven pickups that did that also. Finally, my work car is a 2014 Focus with the (mediocre) dual-clutch auto/manual, and even it does that.
You may well be on the right track with looking at the accessories.
You may well be on the right track with looking at the accessories.
Team Owner
Joined: Aug 2004
Posts: 21,543
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From: Park City Utah
my original thoughts before i started reading about rattle was that it might have been accessory related and I was gonna pull off serpentine belt and see if noise changed, like posted earlier shifts and drives perfect, the noise does seem louder when warm, sometimes non existent when cold, does make a lot of noise when car is lugged like ive read that single masses do. again remember i have no idea whats in car, I havent even checked tranny fluid yet. next on my list to drain and fill with amsoil.
Le Mans Master
Joined: Aug 2015
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From: St. Charles MO
Thread Starter
Instructor
Joined: May 2005
Posts: 193
Likes: 8
From: West Islip NY
I bought it from the second owner who only had it for 2 months and blew a head gasket, the original owner did a lot of work to it, 6 piston brakes with 2 piece rotors, front & rear springs, much larger sway bars, big radiator, full borla exhaust, my guess is it was autocrossed, second owner said 1st owner had just done the clutch, so I doubt the original owner who had so much money in the car did a cheap clutch job, but ill never know whats in there till I take it apart. second owner has no idea how to contact 1st owner for me. car only has 68,000 miles, probably hard miles to need a clutch that soon but car is pretty mint convertible. best is I only paid 2K for it. I did a miniram and a cam, mildly ported stock heads, still need to do headers, gonna disconnect serpentine belt and see whats up, If I don't find anything gonna leave it like most of you have and just make it louder so I don't hear it, lol