I just got an MF 135 that for now I want to use to run a wood chipper. I have the chipper hooked up to the tractor but cant seem to get the lift to do what I want it to do. I don't know if I'm doing something wrong or if I have a problem with the tractor. According to the operators manual I should be able to control the height of the implement with the position control lever. It says to put the draft control lever in the up position and use the position control lever to raise and lower the implement. The draft control lever raises the implement but the position control lever does not do anything. Am I missing something or do I have a problem?