OK, maybe I'm a moron but after doing about 8 trans filter replacements on my 99 Epic 22 I finally figured out how the cap works! Maybe I am the last guy to know this but here is how to do it.
The cover for the filter has a hex nut (1/4 allen) in the center and a tab on the edge that says ATF on it. To remove it insert your allen wrench and turn counterclockwise until the ATF tab hits the housing. HERE'S THE TIP! Keep turning counterclockwise a few more turns and the cover lifts off SO easily. The real benefit is in reinstalling the cap. The hex head you see on the cover is actually a bolt which loosens the lower part of the cover and takes the compression off the large O ring. When you install it with the bolt loosened it goes in sooooo easily. Then as you tighten the hex bolt the ATF tab hits the other side of the housing and allows you to compress the large O ring making a seal.
Again, maybe I am late to the game but I wanted to share my experience. I'm embarrassed to tell you how I used to install the cover and the frustration it gave me.
