It won't climb walls anymore. I have changed the backup valve and the UWF Connector Assembly because they both had cracks. I have also "rotated" the tires because one of the ones that came in contact with the metal gear drive had worn and I switched it with the back one that doesn't have the metal gear. I also checked the RPM's they were about 3o. I've also moved the Thrust Jet to 12 o'clock. After all that when the cleaner reaches a wall it stops AND it looks like the metal gears even stop. HELP!