Hey guys I just recently got this truck running and driving after sitting for 25 years. About a week ago it started to make a strange noise that’s sounds like a loud buzzing/grinding and I believe it’s coming from down by the flywheel/converter area, I can only hear it at certain rpms when idling and when the trans is under high rpm’s going down the road. I put a new starter on it thinking that maybe it was catching on the flywheel but had the same result. I’m new to working on stuff like this and I’m at a loss. Theres a video down below. Any ideas would be appreciated. Thanks
77 mopar 360/727 trans

 

flex plate maybe?

 

Sounds like a flex plate area noise. Could be a bolt backed out holding the converter to the flex plate. Yank the inspection plate off and see if bolts are hitting the inspection plate.

 

I popped it off and everything looks good and tight

 

It's a bit difficult to diagnose without hearing it in person. Does that truck have a heat shield going around the catalytic converter/muffler? If so, check to see if the shield is loose.