Wierd grinding 4th and 5th at high rpm's
07-07-2016, 09:03 AM
#1
Drifting
Thread Starter
Wierd grinding 4th and 5th at high rpm's
I searched the forums for my problem and can't find mention of a like situation...
I've got an MGW shifter, Tick clutch master cylinder, McLeod RST twin disc, LWT flywheel and OEM transmission. During normal driving and shifting through any gear up or down, there are no problems at all, but at high RPM's, say, above 5000, when I begin to push the clutch pedal in, there's a slight brrrrrp sound, almost like I'm grinding gears. It happens within the first 2" of pedal movement, and sounds like it's coming from the footwell. It sure seems like the noise occurs before I row the shifter. The pedal has an extremely slight vibration when it's making that noise. I drive barefoot; I don't think I'd feel the vibration with shoes on--that's how slight it feels. The shifter, the clutch, and the transmission all behave as normal; no sounds, vibration, or anything unusual during this 'brrrrrp'.
One time, I was shifting between 5000-5300 rpm and I heard a funny high-pitched spinning sound from the clutch after I got into the next gear. I didn't miss the shift, but it sounded like something was just let loose to free spin, like "whiiirEEEEE", as if whatever it was, while building rev's under restraint it was let loose. That was 500 miles ago; there hasn't been anything out of the ordinary with about 30 subsequent 5000 rpm shifts. The clutch fluid is clean. The pedal vibration as I depress it and the accompanying noise started immediately during the last outing. No indications of any troubles before that. Nothing on the DIC, the car seems well-mannered during regular driving.
I forgot to add--the clutch passes the "in 1st gear, clutch in, 5000 rpm no movement test".
I'd appreciate your thoughts and ideas!
Anyone?
I've got an MGW shifter, Tick clutch master cylinder, McLeod RST twin disc, LWT flywheel and OEM transmission. During normal driving and shifting through any gear up or down, there are no problems at all, but at high RPM's, say, above 5000, when I begin to push the clutch pedal in, there's a slight brrrrrp sound, almost like I'm grinding gears. It happens within the first 2" of pedal movement, and sounds like it's coming from the footwell. It sure seems like the noise occurs before I row the shifter. The pedal has an extremely slight vibration when it's making that noise. I drive barefoot; I don't think I'd feel the vibration with shoes on--that's how slight it feels. The shifter, the clutch, and the transmission all behave as normal; no sounds, vibration, or anything unusual during this 'brrrrrp'.
One time, I was shifting between 5000-5300 rpm and I heard a funny high-pitched spinning sound from the clutch after I got into the next gear. I didn't miss the shift, but it sounded like something was just let loose to free spin, like "whiiirEEEEE", as if whatever it was, while building rev's under restraint it was let loose. That was 500 miles ago; there hasn't been anything out of the ordinary with about 30 subsequent 5000 rpm shifts. The clutch fluid is clean. The pedal vibration as I depress it and the accompanying noise started immediately during the last outing. No indications of any troubles before that. Nothing on the DIC, the car seems well-mannered during regular driving.
I forgot to add--the clutch passes the "in 1st gear, clutch in, 5000 rpm no movement test".
I'd appreciate your thoughts and ideas!
Anyone?
Last edited by dork; 07-07-2016 at 11:57 AM.
07-08-2016, 07:41 AM
#2
Drifting
Thread Starter
Anyone have any ideas?
Thank you.
Thank you.
07-08-2016, 07:58 AM
#3
Le Mans Master
It sounds like the clutch is slipping, was it shimmed properly? or NOT shimmed...
https://www.corvetteforum.com/forums...h-install.html
https://www.corvetteforum.com/forums...h-install.html
Last edited by 73Corvette; 07-08-2016 at 08:05 AM.
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dork (07-08-2016)
07-08-2016, 10:19 AM
#4
Drifting
Thread Starter
Hey 73, thanks for posting. I read the entire thread you referenced, and I haven't had any of the symptoms discussed.
I think it was shimmed properly--how can I tell? Aside from this funny noise and extremely slight vibration through the pedal only when I rev above ~5,000 rpm, I don't think I've ever experienced anything else other than clutch chatter, which has diminished almost to being 'unnoticeable' with extended street-driving break-in. (I've only ever rev'd beyond ~4,000 rpm [four] while logging data for my Chuck CoW tune files. I never rev'd beyond ~4,200rpm until after I had ~7,000 miles on the new clutch/accessories installation, so this "problem" is newly-found to me.)
The speed shop that installed the clutch only returned 2 of the 3 Tick shims, so I can only assume they installed the correct one. They've been in business since '97 and from all the internet feedback I've seen, they are renowned for Corvette expertise. I hope they knew what they were doing, but I don't know how to diagnose their work.
The only indication I have that the clutch is correctly done is that at a stop, I can put the clutch in (press the pedal down) and rev to 5,000 rpm and the car won't move at all in 1st gear. Doesn't that prove the clutch isn't slipping? and that the Tick master cylinder is adjusted correctly?
Thanks again.
I think it was shimmed properly--how can I tell? Aside from this funny noise and extremely slight vibration through the pedal only when I rev above ~5,000 rpm, I don't think I've ever experienced anything else other than clutch chatter, which has diminished almost to being 'unnoticeable' with extended street-driving break-in. (I've only ever rev'd beyond ~4,000 rpm [four] while logging data for my Chuck CoW tune files. I never rev'd beyond ~4,200rpm until after I had ~7,000 miles on the new clutch/accessories installation, so this "problem" is newly-found to me.)
The speed shop that installed the clutch only returned 2 of the 3 Tick shims, so I can only assume they installed the correct one. They've been in business since '97 and from all the internet feedback I've seen, they are renowned for Corvette expertise. I hope they knew what they were doing, but I don't know how to diagnose their work.
The only indication I have that the clutch is correctly done is that at a stop, I can put the clutch in (press the pedal down) and rev to 5,000 rpm and the car won't move at all in 1st gear. Doesn't that prove the clutch isn't slipping? and that the Tick master cylinder is adjusted correctly?
Thanks again.
07-08-2016, 11:40 AM
#5
Melting Slicks
You can get some very peculiar noises if the pilot bearing is failing - or has failed. There was some discussion of this on here a couple years back - try a search to see if you can turn up any similar symptoms.
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dork (07-08-2016)
07-08-2016, 02:01 PM
#6
Le Mans Master
[QUOTE=dork;1592586956]Hey 73, thanks for posting. I read the entire thread you referenced, and I haven't had any of the symptoms discussed.
I think it was shimmed properly--how can I tell? Aside from this funny noise and extremely slight vibration through the pedal only when I rev above ~5,000 rpm, I don't think I've ever experienced anything else other than clutch chatter, which has diminished almost to being 'unnoticeable' with extended street-driving break-in. (I've only ever rev'd beyond ~4,000 rpm [four] while logging data for my Chuck CoW tune files. I never rev'd beyond ~4,200rpm until after I had ~7,000 miles on the new clutch/accessories installation, so this "problem" is newly-found to me.)
The speed shop that installed the clutch only returned 2 of the 3 Tick shims, so I can only assume they installed the correct one. They've been in business since '97 and from all the internet feedback I've seen, they are renowned for Corvette expertise. I hope they knew what they were doing, but I don't know how to diagnose their work.
The only indication I have that the clutch is correctly done is that at a stop, I can put the clutch in (press the pedal down) and rev to 5,000 rpm and the car won't move at all in 1st gear. Doesn't that prove the clutch isn't slipping? and that the Tick master cylinder is adjusted correctly?
That proves it is DISengaging... but when it's engaged at higher rpms under a load it may be slipping...
Just my guess...
I think it was shimmed properly--how can I tell? Aside from this funny noise and extremely slight vibration through the pedal only when I rev above ~5,000 rpm, I don't think I've ever experienced anything else other than clutch chatter, which has diminished almost to being 'unnoticeable' with extended street-driving break-in. (I've only ever rev'd beyond ~4,000 rpm [four] while logging data for my Chuck CoW tune files. I never rev'd beyond ~4,200rpm until after I had ~7,000 miles on the new clutch/accessories installation, so this "problem" is newly-found to me.)
The speed shop that installed the clutch only returned 2 of the 3 Tick shims, so I can only assume they installed the correct one. They've been in business since '97 and from all the internet feedback I've seen, they are renowned for Corvette expertise. I hope they knew what they were doing, but I don't know how to diagnose their work.
The only indication I have that the clutch is correctly done is that at a stop, I can put the clutch in (press the pedal down) and rev to 5,000 rpm and the car won't move at all in 1st gear. Doesn't that prove the clutch isn't slipping? and that the Tick master cylinder is adjusted correctly?
That proves it is DISengaging... but when it's engaged at higher rpms under a load it may be slipping...
Just my guess...
07-08-2016, 02:58 PM
#7
Former Vendor
Member Since: Nov 2005
Location: Ossining New York
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St. Jude Donor '07-'08-'09-'10-'12-'13-'14
My personal feelings......
I searched the forums for my problem and can't find mention of a like situation...
I've got an MGW shifter, Tick clutch master cylinder, McLeod RST twin disc, LWT flywheel and OEM transmission. During normal driving and shifting through any gear up or down, there are no problems at all, but at high RPM's, say, above 5000, when I begin to push the clutch pedal in, there's a slight brrrrrp sound, almost like I'm grinding gears. It happens within the first 2" of pedal movement, and sounds like it's coming from the footwell. It sure seems like the noise occurs before I row the shifter. The pedal has an extremely slight vibration when it's making that noise. I drive barefoot; I don't think I'd feel the vibration with shoes on--that's how slight it feels. The shifter, the clutch, and the transmission all behave as normal; no sounds, vibration, or anything unusual during this 'brrrrrp'.
One time, I was shifting between 5000-5300 rpm and I heard a funny high-pitched spinning sound from the clutch after I got into the next gear. I didn't miss the shift, but it sounded like something was just let loose to free spin, like "whiiirEEEEE", as if whatever it was, while building rev's under restraint it was let loose. That was 500 miles ago; there hasn't been anything out of the ordinary with about 30 subsequent 5000 rpm shifts. The clutch fluid is clean. The pedal vibration as I depress it and the accompanying noise started immediately during the last outing. No indications of any troubles before that. Nothing on the DIC, the car seems well-mannered during regular driving.
I forgot to add--the clutch passes the "in 1st gear, clutch in, 5000 rpm no movement test".
I'd appreciate your thoughts and ideas!
Anyone?
I've got an MGW shifter, Tick clutch master cylinder, McLeod RST twin disc, LWT flywheel and OEM transmission. During normal driving and shifting through any gear up or down, there are no problems at all, but at high RPM's, say, above 5000, when I begin to push the clutch pedal in, there's a slight brrrrrp sound, almost like I'm grinding gears. It happens within the first 2" of pedal movement, and sounds like it's coming from the footwell. It sure seems like the noise occurs before I row the shifter. The pedal has an extremely slight vibration when it's making that noise. I drive barefoot; I don't think I'd feel the vibration with shoes on--that's how slight it feels. The shifter, the clutch, and the transmission all behave as normal; no sounds, vibration, or anything unusual during this 'brrrrrp'.
One time, I was shifting between 5000-5300 rpm and I heard a funny high-pitched spinning sound from the clutch after I got into the next gear. I didn't miss the shift, but it sounded like something was just let loose to free spin, like "whiiirEEEEE", as if whatever it was, while building rev's under restraint it was let loose. That was 500 miles ago; there hasn't been anything out of the ordinary with about 30 subsequent 5000 rpm shifts. The clutch fluid is clean. The pedal vibration as I depress it and the accompanying noise started immediately during the last outing. No indications of any troubles before that. Nothing on the DIC, the car seems well-mannered during regular driving.
I forgot to add--the clutch passes the "in 1st gear, clutch in, 5000 rpm no movement test".
I'd appreciate your thoughts and ideas!
Anyone?
Here's my personal feelings on the subject and how we handle stock to VERY modified cars here.
UNDER NO CIRCUMSTANCE do we ever replace CLUTCH SYSTEM HYDRAULICS. Simply,
you invite problems and typically gain nothing.
That being said, we use either ZR1 Clutches or our own line of Custom KEVLAR ZR1 or ZO6 clutches. Using the GM proven
design we have minimized any potential problems and the customer gets a very RELIABLE and STOCK FEELING APPLY AND RELEASE.
For a car that has no need for a "racing" clutch or F'd up modified "racing" hydraulics.... Total waste of time and not necessary.
This also goes for BRAKE MASTER CYLS.... People come in with modified ones all the time complaining about how they feel....
INTO THE TRASH THEY GO. The fastest race car out there can do just fine with a stock master.
That being said, given the sound "whiiirEEEEE" you described, It sounds to me like you broke a synchro in the trans because of an
improper shift.... I'll go on a limb here and suggest it's due to the different clutch and master...and a wee bit from the driver.
Again, we get them in here all the time and that aftermarket stuff just never works out....and it's expensive too.
A stock or CoW CLUTCH would suit you much better.
Chuck CoW
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Pounder (07-08-2016)
07-08-2016, 03:01 PM
#8
Le Mans Master
Well...that doesn't sound good 
08-25-2016, 05:31 AM
#9
Intermediate
Here's my personal feelings on the subject and how we handle stock to VERY modified cars here.
UNDER NO CIRCUMSTANCE do we ever replace CLUTCH SYSTEM HYDRAULICS. Simply,
you invite problems and typically gain nothing.
That being said, we use either ZR1 Clutches or our own line of Custom KEVLAR ZR1 or ZO6 clutches. Using the GM proven
design we have minimized any potential problems and the customer gets a very RELIABLE and STOCK FEELING APPLY AND RELEASE.
For a car that has no need for a "racing" clutch or F'd up modified "racing" hydraulics.... Total waste of time and not necessary.
This also goes for BRAKE MASTER CYLS.... People come in with modified ones all the time complaining about how they feel....
INTO THE TRASH THEY GO. The fastest race car out there can do just fine with a stock master.
That being said, given the sound "whiiirEEEEE" you described, It sounds to me like you broke a synchro in the trans because of an
improper shift.... I'll go on a limb here and suggest it's due to the different clutch and master...and a wee bit from the driver.
Again, we get them in here all the time and that aftermarket stuff just never works out....and it's expensive too.
A stock or CoW CLUTCH would suit you much better.
Chuck CoW
UNDER NO CIRCUMSTANCE do we ever replace CLUTCH SYSTEM HYDRAULICS. Simply,
you invite problems and typically gain nothing.
That being said, we use either ZR1 Clutches or our own line of Custom KEVLAR ZR1 or ZO6 clutches. Using the GM proven
design we have minimized any potential problems and the customer gets a very RELIABLE and STOCK FEELING APPLY AND RELEASE.
For a car that has no need for a "racing" clutch or F'd up modified "racing" hydraulics.... Total waste of time and not necessary.
This also goes for BRAKE MASTER CYLS.... People come in with modified ones all the time complaining about how they feel....
INTO THE TRASH THEY GO. The fastest race car out there can do just fine with a stock master.
That being said, given the sound "whiiirEEEEE" you described, It sounds to me like you broke a synchro in the trans because of an
improper shift.... I'll go on a limb here and suggest it's due to the different clutch and master...and a wee bit from the driver.
Again, we get them in here all the time and that aftermarket stuff just never works out....and it's expensive too.
A stock or CoW CLUTCH would suit you much better.
Chuck CoW
just trying to learn what not to do
08-26-2016, 03:59 AM
#11
Instructor
Hey Chuck, how long have you been working on cars?? Specifically the C5 vette platform?? You do realize the stock gm clutch master cylinder is junk don't you? My 02 z-06 clutch pedal would not come back up and stay stuck to the floorboard anytime I tried to shift it at redline. An aftermarket tick solved that problem.
08-26-2016, 04:07 AM
#13
Intermediate
Hey Chuck, how long have you been working on cars?? Specifically the C5 vette platform?? You do realize the stock gm clutch master cylinder is junk don't you? My 02 z-06 clutch pedal would not come back up and stay stuck to the floorboard anytime I tried to shift it at redline. An aftermarket tick solved that problem.
at 90 thousand miles, sounds like your stock one just needed a rebuild
Last edited by charleseawright; 08-26-2016 at 04:40 AM.
08-26-2016, 04:39 AM
#14
Instructor
Since you agree with Chuck, tell me how an aftermarket McLeod twin disk clutch and tick clutch master cylinder caused whatever the noise is he's hearing? Also he said the car ran and shifted fine after he heard the noise, if he has a broken syncro he wouldn't be able to shift.
08-26-2016, 04:52 AM
#15
Intermediate
you can shift without syncros... rev match and double clutch
but since it only happened in one gear it seems more like a syncro-may be the thinking behind that
but since it only happened in one gear it seems more like a syncro-may be the thinking behind that
08-26-2016, 05:21 AM
#16
Instructor
He doesn't just hear it in 1 gear, he hears it every time he pushes the clutch almost all the way in when he's at 5000 plus rpm's. The more I think about it, I think he's got a bad throw out bearing and that's the grinding noise when the clutch is being depressed. Yeah I know you rev match and shift without using clutch but he never said he was having to do that.
08-26-2016, 05:27 AM
#17
Instructor