Third Gen Turbo Diesels use right hand threads for the clutch hub whereas Second Generation used left hand threads. The factory electrically controlled clutch works great (until it fails; then you buy another one). The Horton was sold as improving power and mileage, as well as having total and positive engagement. It was very loud when engaged, of course. I once dyno tested my 1997 with the stock fan and no fan at the 600 HP level and the difference was only 4 HP. Therefore, I don't see how the Horton or similar fan could do much for mileage or power. I recently had to replace my fan clutch on my 2004, and went with another stock unit.