My newest gremlin is a thumping/knocking noise. I thought at first it was a rod knock. No noise when cold. After it warms up (a little) it makes a thumping noise at idle. It does not make the noise in park, only in gear. I put the car in the air and listen with a stehiscope. I can hear it clearly at the oil pump and in the oil pan. I can also hear it clearly in the rear of the trans. If i rev the engine the noise goes away. If i put it in park there's no noise at all at any rpm. I thought flexplate butt if so it should make noise all the time, not just after warming up some. I've never seen a trans noise being so audible all the way to the oil pump. Any thoughts?????????????. Help or ideas appreciated. Still planning on running Fontana on the 5th. If it breaks I'll know what it is huh.