Since you have done many american trannys, taking it out should not be much of a problem. One thing you mentioned caught my eye. The slow engaging reverse is your front reverse clutch drum frictions wearing out, and the leak may be the old style front pump. While you have it out to reseal you should pull the front clutch pack out and replace the frictions and also replace the front pump with the updated style. These are two critical issues with these trannys. Good luck!