My clutch started making a grinding/groaning type of noise last weekend.

This was at the Chicago 1/2 Mile Event before I made any passes. Saturday, I got in the car and helped dry the track. Cruised back and forth after it rained on the runway, using the clutch a lot but actually being quite gentle since it was wet. Drove to the hotel a couple hours later in pouring rain. I don't know if this is related to how the problem started.

The next morning, I head to a gas station and fill up. As I go to leave, I hear a load groaning/grinding noise coming from where the clutch would be. So here's what happens. The issue only seems to occur when I am stopped or barely moving. It only happens when the clutch is slipping to get going. I tested it in 1st, 2nd, and reverse gears. Once the clutch is fully engaged, the noise goes away. If I press the clutch all the way in, the noise goes away. It makes no noise at all unless I'm slipping it to get moving from a stop. Just idling and cruising there is no noise ever. I say grinding, because I can feel it in the clutch pedal. It's a bad vibration/grinding feeling that feeds back through it any time the noise occurs.

So before making any runs at the 1/2 Mile, I left the event and tested it on the street to see what happens in normal driving and full power. Noise happens when slipping to get moving from a stop, once clutch is fully engaged and my foot is off the pedal...it's perfectly fine. From that point forward, there are no problems ever. It handles full power just fine, shifts perfectly, and never has any noise or sensation through the pedal. Only when I came to a stop sign to a full stop, then slipped the clutch to get moving again, did the problem occur.

I can try and take a video.

Any ideas on what this might be? I made 4 passes at full power and did exactly what it should have done on a very hot day, running consistently 154mph (slow first pass to see what would happen), then 157, 157, 157. Then drove the car home 3 hours without an issue. I got gas before leaving Chicago, and the noise actually STOPPED completely. It was perfectly fine. Dropped my buddy off near home 2.5hrs later, and by the time I got to the first stop light and stopped...it started up again when I went to get rolling.

I'm stumped, and am hoping it's something simple so I don't have to remove everything. Odd since the clutch handles all 638rwhp perfectly fine all day long. The clutch is a McLeod RST (installed 2012) with a new master/slave cylinder replaced last year.

 

Possible pilot bearing on it's way out?


I know you don't want to remove but...if you did, unless you ave an aftermarket bellhousing, the C5 bellhousing is 2 piece, pretty easy to take of the bottom section, so you could make sure nothing else major was happening...like perhaps a strap to hold the pressure plate to itself.

Really hard to tell...or test, being that intermittent.