My 904 valvebody

It's been posted before that the reverse servo adjustment can be backed all the way off so the band strut can be removed; allowing the arm to swing out of the way. Push on the band upper tang with a screwdriver to pop out the little square strut plate. If the servo shaft seal is leaking, just chisel off the nub that stops the shaft from coming out, push it back far enough to remove the oring, blast it off with carb cleaner, dry, replace the oring and silicone it back in. They didn't have silicone in 61 when this trans was invented but now there are a lot of modern applications where silicone is used in leiu of gaskets or orings.