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I've been fighting a vibration issue with my c5 for a little while and I'm totally stumped as to what it could be.
A little background on the car.
It has 94k miles
Harmonic balancer replaced with another stock unit at 74k,
Trans rebuilt (sheared 4 gear keys) and torque tube bearings and guibos replaced at 80k,
Clutch replaced at 60 k (vibration existed) by previous owner then replaced again by me at 83k to try and cure vibration (monster lvl2)
And differential mount replaced.
All appeared fine while driving until I started to track the car a little. And found if holding the rpms above 3800-4000rpm (like when going between esses or other steady state throttle conditions) there is a pronounced vibration that gets worse as you keep it at that rpm. When trying to test while stopped, the car will vibrate above this same rpm, and is unaffected by whatever you do with the clutch, whether its in or out, in gear, neutral, the intensity of the vibration doesn't attenuate. It gets a little worse over 4k, and is really only noticable at part throttle, maybe because it doesn't spend too much time at any one rpm when at WOT.
Also of note, I have an LS7 exhaust manifold and X pipe setup, but that was clearanced wherever it needed to be (I hope).
Anyone else had this experience?
I REALLY hope its not the flywheel
Did you inspect the torque tube couplers when you removed it? To me it sounds like torque tube couplers could be bad being that the car has high mileage. Actually putting a new clutch should make the vibration worse since the new clutch will grab a lot harder putting more stress on the drive train. Is there a vibration when reving the engine standing still? Or only while moving?
Did you inspect the torque tube couplers when you removed it? To me it sounds like torque tube couplers could be bad being that the car has high mileage. Actually putting a new clutch should make the vibration worse since the new clutch will grab a lot harder putting more stress on the drive train. Is there a vibration when reving the engine standing still? Or only while moving?
The guibos were replaced when the trans was rebuilt as were the torque tube bearings. This vibration is there whether the drive shaft is turning or not (clutch disengaged, in gear)
Ok so now we can rule out the drive train from torque tube to the rear end...did you put a new flywheel or resurfaced it?
The flywheel was replaced with a Monster lvl 2 lightweight flywheel. It was suspected that the flywheel that was on the car was out of balance (unknown whether original or not, but clutch was replaced) and a cyclical vibration (comes and goes passing through an RPM) that i was getting at 2000-2200rpm was gone, for what thats worth.
I had this exact same vibration, it was weird it was faint at first then continued to get worse to the point where it was bad. I took it to speed inc and had purchased a torque tube rebuild kit from rpm transmissions thinking the couplers went bad and when speed pulled my torque tube it ended up being my input shaft. It was bent and had a ridge. It destroyed my pilot bearing and it was gone! My suggestion is have it pulled and inspected to prevent further damage.
End result is I went with a stock replacement input shaft did the rpm torque tube rebuild kit (new couplers) while they had it apart and it's been great ever since.
Last edited by c6speedjon; 03-08-2016 at 01:40 AM.
I had this exact same vibration, it was weird it was faint at first then continued to get worse to the point where it was bad. I took it to speed inc and had purchased a torque tube rebuild kit from rpm transmissions thinking the couplers went bad and when speed pulled my torque tube it ended up being my input shaft. It was bent and had a ridge. It destroyed my pilot bearing and it was gone! My suggestion is have it pulled and inspected to prevent further damage.
End result is I went with a stock replacement input shaft did the rpm torque tube rebuild kit (new couplers) while they had it apart and it's been great ever since.
Do you still think this is the case even though it will do this vibration when the input shaft is stopped (i.e. transmission in gear foot on the clutch)
The vibration is felt most in the shifter, but if kept at that RPM long enough it migrates to the pedals and a little the seat. The shifter doesn't buzz, you just feel it when you rest your hand on the shift ****.
I had all the work done at a fairly well respected corvette specific shop, so I didn't do it myself.
Also, It's been this way for over 10k miles and 3 track days (one of which was on a bad differential mount)
Last edited by Lemansz06fan; 03-08-2016 at 01:57 AM.
Any time you buy a FW/clutch setup take it in to get balanced, even if the MFR says its not needed. Thats a lot of weight spinning around if its off some it will irritate the snot out of ya.
Hey lemansz06fan, did you ever resolve the vibration? I'm curious if the mounts were the culprit?
the mounts did not solve the issue. I think the new clutch and flywheel may have been installed as is (even though balanced as a set from factory) so there may be a slight imbalance that shows up at 4k off throttle. Its been like this for a long while, so I'm going to live with it for now. Until future plans come to fruition... hehe
Well, thought I'd update this post. The mounts helped but the rear source was the torque tube bearings and couplers. Remenber in the begining I said my FRIEND replaced the clutch and rebuilt the torque tube? Well, he didn't rebuild the torque tube. The bearings were old, one coupler was broken and the other was nothing but a pile of s*$!. I had a guy at the shop I work at take everything out and replace it. Now she's as smooth as a baby's south side!
03-07-2016, 10:01 PM
Vibration issue with c5z
