While driving down the road in 5th gear today I heard a loud POP and the engine free revved. I thiught 5th gear nut had backed off so I pulled down into 4th to no avail. Instantly I knew I had broken an input shaft. Pulled the transmission and sure enough that was the case. I have an NV4500 with a Carolina Clutch cerametallic disc. After pulling the transmission and pulling the clutch I found that my clutch had been slipping also. Can anyone advise the beast place to purchase a heavy duty mainshft for a reasonable price. Is installation very difficult. Any special steps to perform when replacing. Thanks for any help in advance.