The NV4500 was the initial manual transmission of choice for the 2nd Generation Cummins that Ram continued to use through 2004 before being replaced by the 6 speed NV5600. The NV45 is widely popular in many applications due to its relative strength and parts availability. Really, this 5 speed's only faults were the original 12.25" flywheel and some issues with the fifth gear retaining nut. But, as with all things, the stock clutch will give out over time and use. If you use your truck as a truck and are ready for an upgrade that will last, you need to check out this clutch kit from Clutch Masters. And before you ask, no, just because its a dual disc doesn't mean its only for high horsepower trucks. In fact, this particular Street Twin Disc is perfectly suited for trucks up to 1400 foot pounds of torque that are daily driven and frequently tow.
The 1200 Series is a larger diameter assembly, which is designed for high torque output applications. This delivers a higher holding capacity, making it an ideal candidate for heavy towing applications. The 1200 Series Twin Disc features one sprung disc, creating a slightly smoother engagement compared to two rigid discs.