Noisy Trans

99 Grand Am 4 cyl with 115,000 miles has noise from trans when starting engine and lots of noise immediately when shutting engine off. Trans has been flushed. Trans has no notable problems in operation while driving.

Check the flywheel assembly. It sounds like it may be cracked or loose. This can happen at any time and if you are having issues with noise at start-up and after shutting off the engine it sounds like a flywheel issue rather than the tranny.