Something to keep in mind with the NV4500, they are very sensitive to prper lube. On the right PTO cover plate, there is a sticker that has the part number for the correct lube, which is a Castrol brand synthetic 50 weight. Use of anything els will destroy the synchonizers. I've seen this firsthand with a '91 K3500. They owner went through 3 transmissions because he insisted on filling it with 90 wt gear oil instead of the correct lube. It was so sloppy that you could drop it into first gear from a dead stop with only a slight push of the shifter without touching the clutch and the engine idleing (truck was a 6.2 Deisel).
