I have a 1996 GT 275 with Hydrostatic Tansmission. When I step on the forward pedal it will drive very slowly. Reverse does not move at all. One thing I did notice is that my Free Wheel- the linkage that you pull when you want to push pull or tow it- will pull out but I am not able to push or pull the tractor. Does anyone know what might have happened. I appreciate any help that could be given.