Talked to A and A

Not sure if this will work on a 904 but I've changed the levers on 727's without pulling the trans. or engine. Drop the starter and take off the access plate and you can use a 1/4" drive wobble extension to slip in and remove the pipe plug that holds the lever pin in place. Then slide the pin just far enough out to swap the lever and push the pin back in place. Clean the pipe plug and put some pipe sealer on it and reinstall it. I'd say it's worth a shot. If you can't get into it those are all pieces you'd have to take off anyway to get the trans. out.

I thought about mentioning bypassing the accumulator spring and installing a solid blocker rod to hold the piston in place but with lower stall converters it can slam into gear pretty hard. If your running a high stall converter (at least 2500) it will absorb a lot of that shock. Some guys don't mind it, some do.