Developed a nasty rattle at the end of my cruise tonight, help appreciated

[oldmansmonte]

Went on a 20 minute cruise tonight. Ran her a little hard but nothing crazy. Got in the driveway and heard this.

Car has a 350 motor, 200r4 trans. The sound is coming from the mid section around the transmission. Does it in drive and in park. I checked for anything obviously loose or hanging and didn't see anything. Car is piping hot so I couldn't poke around too much, Thoughts appreciated.

(I placed this thread in exhaust because I wasn't sure where to place it. Mods feel free to move)

 

[303'505rollin]

Flywheel

 

[ELCAM]

Sounds like it might be the flex plate.

Check the bellhousing bolts.
Check the torque converter to flex plate bolts.

If you don't find it there might be flex plate to crankshaft bolts.

Edited to add you might have cracked the flex plate inspect the flex plate when checking the torque on the torque converter to flex plate bolts.

 

[oldmansmonte]

Sounds like it might be the flex plate.

Check the bellhousing bolts.
Check the torque converter to flex plate bolts.

If you don't find it there might be flex plate to crankshaft bolts.

This is along the lines of what I'm thinking. Going to get her up on jack stands tomorrow and start poking around.

 

[Texas82GP]

I think ELCAM is on it. Here's a video from YT of a busted flexplate...

 

[oldmansmonte]

I think ELCAM is on it. Here's a video from YT of a busted flexplate...

Sounds very similar

 

[ELCAM]

If you cracked the flex plate and all the bolts were proper it is likely torque converter ballooning that did it. You have more engine than your torque converter can take,

Ballooning is the oil inside the converter under enough pressure to expand the converter in diameter and length.

Problems with ballooning:
1. The converter and transmission pump will fail prematurely.
2. Flex plates will crack.
3. Crankshaft thrust bearing will wear out prematurely.

 

[oldmansmonte]

If you cracked the flex plate and all the bolts were proper it is likely torque converter ballooning that did it. You have more engine than your torque converter can take,

Ballooning is the oil inside the converter under enough pressure to expand the converter in diameter and length.

Problems with ballooning:
1. The converter and transmission pump will fail prematurely.
2. Flex plates will crack.
3. Crankshaft thrust bearing will wear out prematurely.

Holy $***


Really hoping not. transmission was built by Competition Transmission in North Tonawnda NY. They used to building serious race level stuff and the owner himself built mine because of the complexity of the 200r4. He chose the torque converter based on my motor and cam specs which is a 330 horse GM crate motor. Nothing too wild.

 

[ELCAM]

Loose bellhousing bolts will crack the flex plate too. Hope for that it still sux to fix but is a lot cheaper.

 

[pontiac guy]

A manual transmission will also fix flexplate issues. Just saying. 😉