We had trouble with the starter in our Gehl. I think it's a 5640. More importantly it has the Duetz diesel engine. Is that what you have? We got two new starters from the dealer and they both had junk solenoids on them. Try tapping the solenoid after you start the engine, that might get it to let go. If not, you probably need to replace the solenoid, if it's a separate unit, or the entire starter.