01 47re.... rebuilt it with Dave Goerends guidance for $1400 80K miles ago. Putting down 700lb ft torque. Tows my loaded race trailer 75mph up a 6% grade if I feel like beating on it (egt through the roof so I only did this once.... ). 47/48 can live. NV5600 are good.... but don't break it!! parts availiblity getting pretty bad.