I have a 2006 DK40 with the manual shift 4wd. Push the lever down to engage the 4wd, pull the lever up to disengage. My problem is it has always been a little tough to disengage the 4wd but this time I used my tractor for about 8 hrs and I can not get the 4wd to disengage. I have tried different gears, speed, neutrals, reverse, forward and nothing seems to get it out. Any Ideas would be great.