Full Race weird noise from gearbox..?

[zachs the name]

Hello all, I recently bought the full race exhaust for my si and i have been having problems with it at random moments. It first started with a constant thudding sound (as if i had a flat tire) coming from my front right tire, i checked to make sure and no flat tire. as i continued to drive, my gear box started to vibrate constantly followed by an excessive sound of loud air flow coming from my gear box (i believe it is where the catalytic converter and the flange meet). i checked under the car immediately when i got home and there was no leaking, or unwanted airflow from the piping. Every bolt is tight from the converter to the muffler.Ive ran out of possibilites. Any thoughts?

 

[webby]

@squiggy may have advice or areas to check

 

[squiggy]

It first started with a constant thudding sound (as if i had a flat tire) coming from my front right tire

The exhaust wouldn't have anything to do with this.

as i continued to drive, my gear box started to vibrate constantly followed by an excessive sound of loud air flow coming from my gear box (i believe it is where the catalytic converter and the flange meet). i checked under the car immediately when i got home and there was no leaking, or unwanted airflow from the piping. Every bolt is tight from the converter to the muffler. Ive ran out of possibilites. Any thoughts?

Not a clue. This is weird.