Hello all, my grasshopper 720k drove fine all the way down my .5 mile long drive way to my front field. I stopped and shut it off to cut out some trees before I started mowing. Upon restarting the left wheel would not go forward, right works perfect. Left wheel will go in reverse fine as I had to back down entire driveway to get back home. All the linkage looks good, and fluid is good. Any suggestions?