clunking 3k stall torque convertor

[DarkoStoj]

I just bought a 78 trans am and it has a 3k stall in it. When I first start the car when its cold I hear clunking noises coming from the transmission/torque convertor but go away when it warms up. Is this normal or what could the problem be?

 

[91trunk]

Loose nut behind the wheel.

 

[Sean124]

could be the converter drain back check ball is missing.