I had the same problem with mine when I first got my truck. It was all gumped up inside from lack of use. My father took it apart ,since I was only 8 years old at the time, and cleaned and greased it, and it has worked great for the past 22 years. Has yours always been jammed or is it a new problem? I have a manual for the winch that shows all the parts and assembly. I could send you a copy if you like.

Jeremy