I have a 4110 with 4WD and front end loader (250 hours) The other day I was driving the tractor and the tractor made a bumping sound along with sort of surges. I had a hard time getting the tractor out of 4WD, but it ran fine after that. Now I can't get it back into 4WD. The lever/linkage seems to be moving, but maybe not far enough. What could it be? What can I try?