Hi to all, I need some major help

. I have a 4.0, 03 Ford Explorer Sport with a noise in the tranny or somwhere in that area. I have been to many mechanics who can not find this noise but can hear it. I have also been to three different tranny shops and this noise can't be pin pointed. The noise I am having sounds like a knock in the motor but some where in the tranny area. I have possibly narrowed it down to a flex plate or a torque converter? The noise is heard when put in gear (R, D, N) and the windows in the up position so you can really hear it. I first checked the tranny fluid and it is full.
I had the tranny overhauled last year and heard this noise a couple of months after. I brought it back to the shop and the guys at the shop stated it was not the tranny and charged me $60.00 to look at it. (right

). Any one else had this problem??? Thanks