Vibrating C7
Thread Starter
8th Gear
Joined: Sep 2023
Posts: 8
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From: New Orleans
Vibrating C7
What’s up? I have a manual transmission c7. Before I got it serviced it was vibrating by the clutch shifter. I had to replace the clutch and I got the flywheel resurfaced but now I still have the same vibration.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
1) No idea what a clutch shifter is
2) The flywheel is a dual mass flywheel and it's not designed to be resurfaced.
3) The flywheel is balanced with the crank/rods/pistons. Resurfacing and/or random installation can cause engine damage
3) "replacing the clutch" is a broad description. Pressure plate? Clutch disc? Clutch Release Cylinder? All of the components?
4) There is no physical connection between the clutch assembly and the shifter. It bolts to the torque tube and the linkage goes aft....to the transmission.
If you took it somewhere, I'd say you got screwed. If you did it yourself, this is why there are factory service docs.
2) The flywheel is a dual mass flywheel and it's not designed to be resurfaced.
3) The flywheel is balanced with the crank/rods/pistons. Resurfacing and/or random installation can cause engine damage
3) "replacing the clutch" is a broad description. Pressure plate? Clutch disc? Clutch Release Cylinder? All of the components?
4) There is no physical connection between the clutch assembly and the shifter. It bolts to the torque tube and the linkage goes aft....to the transmission.
If you took it somewhere, I'd say you got screwed. If you did it yourself, this is why there are factory service docs.
Burning Brakes
Joined: Mar 2022
Posts: 1,220
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From: Phoenix, Arizona
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,621
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From: Cape Coral, Florida
Find a shop that can do NVH (Noise, Vibration, Harshness) testing....other than that you will only be guessing...now dealerships should have a Picoscope and the accelerometers to do this testing...maybe !!....other shops that use this advanced testing equipment can pinpoint it for you....vibrations can be difficult to diagnose without this advanced testing equipment.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
The actual flywheel itself is neutral balanced. The factory adds balancing "pins" as needed when the assembly is balanced. When you install the new flywheel, you install balancing pins in the same location as they were installed on the old flywheel. You then use your reference marks to install it in the same position on the crank as the old flywheel.
GM used to do this in reverse on the later C4s. The crankshaft balancer would have pins in it and if you replaced the balancer you had to install pins in the same place. I have a bag of the pins laying around somewhere. Back in the day GM had a specific part number for the Gen 2 LT4.
