I work for a shop called Motor Technology Inc. in Soth Central PA. We rebuild industrial electric motors. With a warn, it is more than likely a series wound motor. Just an fyi, check your resistance across all fields, they should be all close, if not, you will need a rewind. We charge $80/hr, if it needs rewound you are more than likely better off buying new. A rewind will need to be done by a specialty shop and will more than likely be pretty expensive.