Shifter Troubles

hi, inside the trans, there is a shoe on 1-2 arm, it rides over the reverse arm, to prevent being in two gears at once. if they do not clear each other, shifting into reverse is a chore. you can adjust shifter all you want, still will be hard to get reverse. the proper way to fix, is to loosen up side cover, shift into reverse, then tighten back down. now, the reverse will work better. I have changed side covers and had to grind on the shoe to make them fit properly. they are not the same!! I've done this before. just food for though.