Yep, I was wrong and had to look your model up on tractor data which indicates it was only available in a gear drive model. I was thinking it was a hydrostatic like my L47. My gear drive M5 has a lever on the left too but it’s a forward reverse shuttle and you would know if that’s what yours did. Sorry, I don’t have a clue. Is your lever orange? If so, it should be tractor motion related.It dose nothing when moved. Talked to the original owner of the tractor and he is pretty sure it did nothing from day one