I'd have the grease shop 500 yards from my house do a trans change and I don't think they carry K&N filters... But I do know the trans fluid has been changed at least about a year and a half ago, becuase the tranny had some work done to it when my dad took it for a test drive he put it into overdrive, the normal gear for driving. My boss always drove it in regular D, and it exploded. So they must have had drained and refilled it when they did work on it, right? I guess it'* getting to be about that time for a change as well...

Its Feasible to think that one could go to a local parts store, or search online and get a universal adapter, something with a cone filter tube fitting on one side and a flat bracket on the other. Use that and get a filter to match, and mount it and seal it off INSIDE THE GUTTED AIRBOX

all of this assuming you have the actual room to do so inside the box... just a thought to toss up in the air

Something like this