Gears Grinding
Race Director
Joined: Apr 2017
Posts: 10,247
Likes: 888
From: Hickory NC
2025 C5 of the Year Finalist - Modified
2022 C5 of the Year Finalist - Modified
2020 C5 of the Year Finalist - Modified
St. Jude Donor '17 thru '26
A little more information would help.
Is this when shifting into any gear above 3000rpm?
Does it grind on upshifts and downshifts?
Year and mileage?
Any recent work to your Vette?
Does it always make the noise or only when the engine/trans is cold or hot?
When you put in the clutch above 3000rpm do you have the noise or only when releasing the clutch and engaging the gear? Does the noise continue after you are in gear or quit once the clutch is released?
Several possibilities come to mind and I'm sure others will have even better ideas, but it could be the throw out or clutch roller pilot bearing; or synchros; clutch linkage; the clutch itself; and even possibly a motor mount. (If you have a worn or broken motor mount this will put a load on the torque tube which in turn adds a load on the transmission due to the changed angle).
How old is your trans fluid? It’s possible replacing the fluid will help.
A possible test: Try double-clutching (for example, when shifting from 1st to 2nd depress the clutch, shift into neutral, let the clutch out, then push clutch down and shift to the next gear. If that makes the noise go away, then you probably have worn synchro rings and possibly the bearings are worn excessively.
Good luck.
Is this when shifting into any gear above 3000rpm?
Does it grind on upshifts and downshifts?
Year and mileage?
Any recent work to your Vette?
Does it always make the noise or only when the engine/trans is cold or hot?
When you put in the clutch above 3000rpm do you have the noise or only when releasing the clutch and engaging the gear? Does the noise continue after you are in gear or quit once the clutch is released?
Several possibilities come to mind and I'm sure others will have even better ideas, but it could be the throw out or clutch roller pilot bearing; or synchros; clutch linkage; the clutch itself; and even possibly a motor mount. (If you have a worn or broken motor mount this will put a load on the torque tube which in turn adds a load on the transmission due to the changed angle).
How old is your trans fluid? It’s possible replacing the fluid will help.
A possible test: Try double-clutching (for example, when shifting from 1st to 2nd depress the clutch, shift into neutral, let the clutch out, then push clutch down and shift to the next gear. If that makes the noise go away, then you probably have worn synchro rings and possibly the bearings are worn excessively.
Good luck.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
I agree on MORE INFO.. 
Year of C5
Mileage
Mods
When was the last time that you changed/check the master cylinder fluid????
First thing that I would do is check the master cylinder fluid. I bet ya a cold one that its BLACK AND NASTY!
Use the ranger Method to get it clean again.
Change the transmission gear ATF. Yours (if its never been changed) will most likely look like dark metal flake paint!
Use the correct AMSOIL ATF ( I use the Torque Drive ATF) AMSOIL has since up-dated their line of ATF fluids and I think it now called signature series. Contact AMSOIL for the best info..
Bill
Year of C5
Mileage
Mods
When was the last time that you changed/check the master cylinder fluid????
First thing that I would do is check the master cylinder fluid. I bet ya a cold one that its BLACK AND NASTY!
Use the ranger Method to get it clean again.Change the transmission gear ATF. Yours (if its never been changed) will most likely look like dark metal flake paint!
Use the correct AMSOIL ATF ( I use the Torque Drive ATF) AMSOIL has since up-dated their line of ATF fluids and I think it now called signature series. Contact AMSOIL for the best info..Bill
