Hello, I have an 02 mustang gt auto with 195k miles, and the problem I’m having is a knock coming from the very bottom of the motor (possibly transmission) that only happens at idle in gear (at 600 rpms) and cannot be heard AT ALL from the top of the engine in the engine bay. The moment I even press the gas the slightest bit, it’s completely gone. And it never knocks AT ALL at any other rpm. Any help is appreciated because I have absolutely no clue what it is. Thank you.