IT sounds alot like dry dead leaves scraping against pavement (Theres a specific sound for ya.) When i first noticed it it was very rare and usually when i would come to a stop at a stop light or something. Then it became more common at most times i was idle and now i can hear it a lot, sometimes when the car shifts gears, when coming to a stop, leaving from a stop, in reverse.

The only time i have yet to hear it was in lock up but one time coming out of lock up i heard it real quick. IT sounds like its coming from the flexplate area but i havent gotten a chance to slide under there yet.

any ideas? Ill try to get video.

 

having the same issue but maybe your flywheel/ rotating assembly is unbalanced? I know mine is internally balanced meaning the flywheel has no weights.

 

My buddies car made the same noise. If progressively got louder and louder. It ended up being the torque convertor.

 

It could also be a bolt backing out and starting to brush up agaist the tc or flywheel.

 

You will need to pull the metal cover off the flexplate.
4 bolts hold it in place, then look at the flexplate near the crank bolts closely with a good light source. Look for any sign of cracking. This happend to me. The noise was more of a metalic rattling, though.

Get the problem fixed asap. If the bottom end is stock, get an external balanced flexplate. IMHO get a SFI approved unit.

 

so i went under there today. Yesterday the sound seemed to go away, heard it a few times when i would shift into reverse but it would only make the noise for a second and then it was gone.

Went under the car today and found nothing. Visually the torque converter and flexplate are both fine. I know you cant really tell much about a TC visually but anyways.. I checked the fluid for the tranny and that also is fine, not burnt, usual color.

So im stumped for now. Im gonna carry my camera with me and if i hear the noise again ill post up a video of it.

here is a seemingly useless pic confirming my findings

 

I wish I had photoshop, but look closely there is something riding on the flywheel looks kinda like a shepherds hook.

 

yeah i see what your talkin about.. i played with it and its not as solid as it looks.. its like piece of gasket or something like that.. its just got oil on it so it looks like its a sturdy piece of something but its soft like a string

 

I once helped a friend diagnose a noise in an old Javelin, and it turned out that the flex plate was cracked from bolt hole to bolt hole all around the flywheel bolts. It was still on there cause it didn't have anywhere it could go, but it was effectively broken off and just sitting there. The car was running like that a while I guess.

 

Did you bump the engine over a few times to look at the flexplate from all angles? Could only see the crack on mine very slightly from one angle.

Pulled the flexplate and it was cracked around all the crank bolt holes.

 

well the noise came back and i got under there to listen this time and i think its definately the flexplate.. heres a quick clip so you guys can shed a little more light on me.



How do I get in there to remove the flexplate or do you think this is a job best suited for some professionals?

 

to replace the flex plate you need to remove the three bolts that bolt the converter to the plate and slide the converter back towards the tranny, then there are six bolts that hold the plate to the crank, this is where it gets a little tricky, you need to loosen - not remove - the bellhousing bolts to back the tranny out a bit to get to the bolts at the crank. it's not that hard, just take your time and be sure to put thread locker on the bolts when you reinstall them - when you get it out, post a picture, I'm thinking you'll find a crack in it

 

my experience with broken flex plates sounds like a rod knocking in the back, loose bolts sound similar and they both did it all the time,

good luck

 

Bringing this post from the dead, I'm having a similar issue. What did you find out? Was it the FP? Any cracks?