Is it mechanical )motor and gear) or hydraulic? If mechanical, odds are the drive pin for the gear on one end of the motor shaft has sheared, so the slide is being pushed only on one side. A new shear pin to lock the gear to the shaft should solve the problem.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL