rattling with clutch - ZR-1 Net Registry Forums

lylehman · 08-22-2017

I have a 1991 ZR-1. when I put the car in neutral and let out the clutch, there is a noise resembling loose nuts/bolts in a coffee can. what is this? should I be concerned and what is the cure?

efnfast · 08-22-2017

Sounds like the dual mass flywheel has been replaced with a single mass. IF that is the case, the noise is nothing but annoying.

Paul Workman · 08-22-2017

Mine rattled a little with the dual-mass. Turned out to be injectors were NOS and succumbed to the ethanol in (IL) gas. But, after the "500" upgrade & the addition of the Fidanza FW, the neutral w/ clutch out rattle has returned. NO biggie.

Hib Halverson · 08-22-2017

Your 91 has the early style ZF and they have a lot of gear rattle in neutral, even with the dual mass wheel. In fact, one reason the later cars had a redesigned trans with gears having increased helix angles was to decrease gear rattle in neutral.

That said, your description has me thinking your dual mass wheel has failed or, as others have stated, at some time before you owned it, somene replaced the dual mass with a standard flywheel.

efnfast · 08-22-2017

Oh, and welcome to the forum.

Bruce · 08-23-2017

My 91 does a similar thing, not quite bolts in a can but a small perceived rattle. I have a ZF DS25 transaxle in another car that does the exact same thing in neutral. Id say its nothing to worry about.

jss06c6 · 08-24-2017

Having just replaced my Fidanza flywheel with a dual mass FW on my '91, I would suggest you are hearing the trans gears rattle without the dampening benefit of the dual mass FW. Mine was a can of rocks with the Fidanza. Now it's butter smooth! I would expect you too have a Fidanza or other standard FW.. the black tag transmissions are rated at 450 lbft. Like the old M-22 rock crusher Muncie's, these straight cut gears are strong, but noisy...

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08-22-2017	#1
lylehman Join Date: Jan 2017 Location: Katy, Texas Posts: 1	rattling with clutch I have a 1991 ZR-1. when I put the car in neutral and let out the clutch, there is a noise resembling loose nuts/bolts in a coffee can. what is this? should I be concerned and what is the cure?

08-22-2017	#2
efnfast Join Date: Nov 2011 Location: Dunbarton NH Posts: 7,255	Re: rattling with clutch Sounds like the dual mass flywheel has been replaced with a single mass. IF that is the case, the noise is nothing but annoying.

08-22-2017	#3
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,493	Re: rattling with clutch Mine rattled a little with the dual-mass. Turned out to be injectors were NOS and succumbed to the ethanol in (IL) gas. But, after the "500" upgrade & the addition of the Fidanza FW, the neutral w/ clutch out rattle has returned. NO biggie. __________________ Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry

08-22-2017	#4
Hib Halverson Join Date: Jun 2005 Location: CenCoast California Posts: 899	Re: rattling with clutch Your 91 has the early style ZF and they have a lot of gear rattle in neutral, even with the dual mass wheel. In fact, one reason the later cars had a redesigned trans with gears having increased helix angles was to decrease gear rattle in neutral. That said, your description has me thinking your dual mass wheel has failed or, as others have stated, at some time before you owned it, somene replaced the dual mass with a standard flywheel. __________________ Hib Halverson Technical Writer former owner 95 VIN 0140 current owner 19 VIN 1878

08-22-2017	#5
efnfast Join Date: Nov 2011 Location: Dunbarton NH Posts: 7,255	Re: rattling with clutch Oh, and welcome to the forum.

08-23-2017	#6
Bruce Join Date: May 2016 Location: Whangarei New Zealand Posts: 29	Re: rattling with clutch My 91 does a similar thing, not quite bolts in a can but a small perceived rattle. I have a ZF DS25 transaxle in another car that does the exact same thing in neutral. Id say its nothing to worry about.

08-24-2017	#7
jss06c6 Join Date: Aug 2015 Location: Magnolia, Texas Posts: 884	Re: rattling with clutch Having just replaced my Fidanza flywheel with a dual mass FW on my '91, I would suggest you are hearing the trans gears rattle without the dampening benefit of the dual mass FW. Mine was a can of rocks with the Fidanza. Now it's butter smooth! I would expect you too have a Fidanza or other standard FW.. the black tag transmissions are rated at 450 lbft. Like the old M-22 rock crusher Muncie's, these straight cut gears are strong, but noisy... Sent from my QTAIR7 using ZR-1 Net Registry mobile app Last edited by jss06c6; 08-24-2017 at 10:35 PM.