hey i got a chrysler 8.25 and have had similar symptoms, especialy not locking in reverse. Which i know that when i got it, it always locked in reverse. I have replaced the springs once with some improvement, but has continued to stop working. I havnt checked any clearance specs but i do know that when rotating tired back and fourth to see the inner workings the center pin seems to have a lot of play, along with it just totally not wanting to stay locked when thrown back wards direction. Mine is a powertrax no slip.