I just purchased a 7711 Zetor which has 1700 hrs. Seems like a good machine overall and I have ordered a shop manual and operators manual. I think I have figured out most of the controls correctly, but there are a couple which are somewhat confusing. There is a short flip lever at the front of the lift arm control and also a short lever at the inside of the lift arm control coming out of the floorboard. It appears to have three positions labeled (I think) "N", "D", & "P". I tried to shift this lever but it seems to be stuck in the "D" position. Can anyone give any insight into the function of these controls and also what might be causing the one to be stuck?