$#@# leaking trans pan.

This is the third time that I will attempt to fix a leak from my 904 factory pan. The first time I just used the fiber looking gasket with no silicone and it leaked. The second time I made sure the suface was flat, used the black RTV and a new fiber gasket. Still dripping. This is the last time I will try it. This time I picked up a rubber gasket from NAPA. Any suggestions? Please help.