keepupp

Hoping for some possible causes to what I believe was a part failure. This evening I was driving in 2nd gear and under a pretty strong application of throttle when BOOM! Loud bang followed by metallic sounds . No fluids or smoke evident. Engine spins freely and clutch feels normal and I can push the shift lever into all gears normally BUT while the shifter is in ANY gear I can release the clutch entirely and it doesnt stall. As a matter of fact the wheels are in neutral and i can roll the car. When rolling the car I can hear some clunking and metal noises towards the rear or the car. My car has a lightweight flywheel and triple disc carbon clutch. I have heard of flywheels breaking in two with 8 bolts being sheared off. Not sure this is the case but I've ruled out engine failure.

Any ideas? Plan on towing to a specialist but wondering what you might think?

TIA

venom51

You likely snapped the input shaft...

keepupp

Is this a documented issue with 997's? Car has about 16k miles. Curious what else may have been damaged.

cbracerx

I assume when in gear the car still rolls freely? Clutch plate(s) failure? No matter what the trans is coming out to investigate. I would not run the engine any longer.

keepupp

Yes, when in gear car rolls freely. Clutch effort hasn't changed and shifter goes into each gear normally yet when clutch is released the car doesn't stall. This morning I inspected underneath the car for fluids and nothing. Engine fires up right away with no stumbling or engine light. When rolling the car you can hear some clunking towards the rear. Car has full bolt ons and a lightweight flywheel and triple carbon clutch.

tgavem

If the mechanism to operate clutch is intact, pedal pressure may not change.

from there, either your clutch plates or springs failed. Transmission is between engine and rear of car so where sounds should come from.
if just the clutch, 3-4K should fix it. Good luck

venom51

I doubt it is common place but you can't rule out a material defect. Could be something let go in the clutch assembly as well. You just won't know until you pull it apart.

JB911

Did you go underneath and look at your drive shafts?

keepupp

I have not gotten underneath the car yet. However, I would imagine the car would still grab gears if a drive shaft were broken. As it stands, I can put it in any gear, release the clutch completely and it isnt engaging the gear. It stays in neutral. Clutch pedal feel is normal and engine runs normal. Something clearly broke due to the big boom and metal sounds and I think the input shaft may be it. Wont know until the trans is dropped and inspected.

keepupp

This turned out to be the culprit. Snapped the drivers rear axle. Good call

cbracerx

Well that’s not a bad outcome! Much easier repair. Surprised it wasn’t noisy.

keepupp

It was very noisy when it broke. Bearings being tossed about making metal on metal sounds made me think it was the engine until I stopped the car and noticed it was still running smoothly and revved freely.

my first 911

I think he meant noisy before it broke