I have a TN75s as well. I think there must be an inherent problem with the ECU for the shuttle. They replaced a switch under the seat and so far so good. I also had to turn it off and restart to get it to move....until I by chance figured out that I had to put it in gear and engage the shuttle lever.....all with the clutch pushed in and then let the clutch out and it worked fine. I could not put it in gear with the clutch out and then move the shuttle lever into forward or reverse and have it move. They replaced the switch under the seat and now it works normally. You might try putting it in gear, depress the clutch and engage the shuttle lever with the clutch in and then let it out and see if you move. Just my experience. Hope it helps....worth a try anyway.