Flex plate rattle?
 

I just bought a 2002 CL600 V12 with 84,000 miles. It has a rattle when accelerating, but as soon as you let off the gas, it goes away. Also, if your moving in reverse and hit the brakes suddenly it rattles for a brief second. It sounds like if you were to drag a screw driver in a large fan. My theory is something is swinging into the flex plate? Could it be a cracked or broke plate? Has this ever been an issue with this model? I have done some searching, but not heard of anything like it. I've already done a lot of work on the car, and am not worried about tearing into it, just want some opinions before pulling the tranny to check it out.

Thanks in advance!
Briley.

Haven't heard of that on the v12, but it does happen from time to time on the v8 cars. Usually you get noises all the time though. Your sound might be something in the front touching the belt drive/fan also, worth checking as it will be easier to fix.

Can you replicate it at all with the car stationary? I'd say put it on a lift and listen underneath when it happens but if it requires accelleration it will be hard to reproduce.

Sure it's nothing contacting the exhaust? Are the mounts in good shape?

I was able to lay on the ground next to the car while someone moved and stopped it in reverse, it's clearly coming from under the car at the flywheel area.

So I forgot an important bit of info. Since I've had it, every once in a while the starter will not engage, it sounds like the bendix isn't engaging and kicking the gear out. If I turn the key off and restart it, it will usually start right up. So, here's a theory, is it possible the starter gear could be sliding out just enough to hit the flywheel gear? I've never heard of this happening before, but I guess a starter is easier than dropping the tranny.

Anyone have a starter how to? :)

Sounds logical, as you said I've not seen one do that, but it's definitely a possibility and would fit the acceleration pattern. I have seen starters failed and the bendix just flops around, so it makes sense to me.