Knocking sound when cold and in drive at idle

2006 4.0/auto - just recently started hearing a fairly prominent knocking noise (very similar to a valve clank) coming from what appears to be just forward of bell housing. If car is cold and in neutral or park I dont hear it even if I rev but the moment I engage in gear I hear this but it goes away as it warms up. The noise increases if I give it gas. I mostly hear it from being under car - Id say loudest between bell housing and oil pan. Ive checked for loose things but am not seeing anything. Trans and motor fluids are at level. Any idea what this could be? am not sure what turns around there when in drive and not neutral though it could be the load making the difference though its odd that I dont hear a thing in neutral.


Video: https://www.youtube.com/shorts/szGW-tCviEk

 

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@Kolter45 just posted

 

Even if i rev hard i park i hear nothing- its hard to believe that rattle would be a rod or something in engine when i only hear in gear and usually at idle/low speed. But besides stuff inside trans i can’t think of anything that moves around engine only when in gear. Any ideas? Ive checked mounts, exhaust mounts etc and looks ok.