jd911

My 99 vert, w/ 6m is quiet as a church mouse when I start her up and back out of the garage. No rattling at all. Take it for a spin, short or long, doesn't seem to matter. Drive it back into the garage and it's rattle city, including one louder rattle when you turn the ignition off.

It sounds like it's coming from the area in front of the rear axle. I don't think it's the clutch, transmission or torque tube, because slipping it into neutral, pushing the clutch in or letting it out, does not change the rattle one iota.

Is there anything inside the catalytic converters that would rattle only when hot? I've had the car up on jack stands, and tried to wiggle the exhaust around and nothing seems loose.

The engine runs superbly, and the exhaust is quite load when you jump on the throttle, so I don't think the cats are plugged or obstructed.

It takes a while to jack it up and get it on jack stands, and by then it's cooled off a bit, so it's been hard for me to pinpoint the problem

Any thoughts, ideas, etc????

Anyone else have hot only, rearward rattle(s)?

Thanks in advance.

Jim

Bill Curlee

Jack her up on four stands. Let it IDLE until its hot again. Grab your favorite rubber mallet and start agitating under body components (exhaust piping and hangers, CATs "yes the honey comb matrix inside the cat can degrade and rattle) tunnel plate, sway bars and springs, ect...) Some exhaust mid pipe flanges have been known to crack and rattle. The exhaust hangers can also make weird rattles when hot and or cold.

Try this: Start the engine. Put the car in Neutral. (parking brake set) let out the clutch. TURN THE ENGINE OFF. As the engine is shutting down, listen to the drive train. You will or should hear a distinct rattling noise. Do the same thing but this time DEPRESS THE CLUTCH before you turn the engine OFF. The noise should not happen.
THATS COMPLETELY NORMAL in both scenarios!

The noise has to do with the clearances of the SPLINE SHAFTS at each drive train splined shaft sliding surface. When the engine coast to a stop the flywheel oscillates CW and CCW slightly just before the engine rotation completely stops due to compression. The lost motion between the spline shafts is what makes the noise.

BC

Andy1982

Have you found and/or repaired your rattling issue since you first posted this thread? I have a very similar problem with my 2011 Grand Sport, except I have an automatic transmission. One member suggested that it probably is the torque tube bearing/coupler located at the rear of the car close to my torque converter. I would be very curious as to what you found if you have repaired it recently. I would also be greatly appreciative if you would post your findings on your car. In advance, thanks for your time.

jd911

I've basically just ignored it thus far Andy. Sorry. I'm still looking for my round tuit.

I have noticed it is not so loud and I really don't notice the sound with the convertible top up.

Jim