After researching why my Sabre lawn tractor wouldn't go , i found great info on this site. I replaced the pulley on tranny, and everything seemed to be in order. That was yesterday. Today I mowed the lawn. When I was nearly done, it didn't want to shift into gear. By fooling with the (parking)brake /tranny interlock, I was able to get it into gear. After I shut it off, I couldn't get it into gear again. It seems to be related to that interlock. any suggestions?