A/T clanking/metal grinding sound at idle

[DSMMMMMMMMMMMMM]

this is my car at idle then shifted to drive then reverse
clanking sound happens every second or 2.
it happens at around 1300 rpm's and below
drives fine just makes that sound when at idle.
it sounds very clear at the end when i turn the car off.


car is fully build awd a/t 2.4 6-bolt block with 2g trans
gt40r, ems,272 cams,cop, etc...
motor is new with around 100 miles on it
it just started doing this a few weeks ago
haven't done anything except replace starter(was goin bad)
also it seems a little harder to crank over now
it sounds pretty loud around the tranny area

any ideas?

change file extension from dat to mp3

 

[toybreaker]

This may be a loose/cracked/damaged flex plate.

Pull the convertor inspection cover, sneak a small dental mirror in between the block and flex plate and give everything a visual inspection.

While you're there, ensure the convertor bolts are tight.

 

[DSMMMMMMMMMMMMM]

what could have caused this?