Help identify bad sounds from gearbox/bellhousing area?

[dsmithwc04]

So after Sunday's race at the June Sprints I noticed a horrible sound coming from the bell housing / gearbox area. I had a ton of work to catch up on when I got home along with getting a new trailer so I've had very little time to work on the car. I had a little time to check the pinion and layshaft nuts were torqued correctly then removed the gear stack and everything looked good upon a quick look over. The sound almost made me think it was the flywheel when I was driving down the pits but I haven't had the time to separate the engine/gearbox yet. Anybody have any ideas to throw out until I have the time to really diagnose the issue?

Here is a 1 minute video of me driving down pit lane. The sound is the worst just as I exit the hot pits.

https://youtu.be/Zd1Ck8sRjeM

[Keith Carter]

I can't really tell from the video, but does it sounds similar to trying to start the car once it's already running with the starter pinion trying to engage a moving flywheel?

[mikey]

I agree this sounds like flywheel issues. Maybe a broken tooth is flying around or maybe the starter is trying to engage or has a broken pinion. Also possibly an issue with the starter button itself or the wiring shorting. Maybe a flywheel bolt flying around also?

[Eric Cruz]

A typical FE failure that can sound like that is the ring gear/flex plate breaking right around the flywheel bolts. Sometimes it breaks clean and simply spins without cranking the motor when you engage the starter, but many times it cracks completely around just outside the bolt circle, remains sandwiched between the flywheel and the crank, and raises quite a ruckus.

Best regards,
Eric

[dsmithwc04]

Well, Eric wins the prize.

EDIT: Okay, they aren't as expensive as I thought. Should have new one on the way.

[Eric Cruz]

Damn, I love it when I'm right! Of course when a bad noise from that area happened on the 2nd lap in a new motor on my T-car in May, we thought it was the flex plate too. Unfortunately, when I pulled the gearbox, saw the plate was fine, and ran it with a replacement and no gearbox, the noise was still there. Shipped back to Enterprises and Shannon found a spun #4 rod bearing. They are handling it under warranty, so not expensive either - just keeps that car off the track waiting on shipping

Best regards,
Eric