Muncie 4-Speed Transmission Rebuild Kit - Allstate Gear Muncie 4-Speed Master Rebuild Kit. We stock a comprehensive lineup of Muncie M20, M21 and M22 car transmission parts, including top-quality Muncie 4-speed rebuild kits. If you're rebuilding a Muncie M20 4-speed wide-ratio manual transmission, we've got the Muncie M20 rebuild kit you require. NP241 Transfer Case Rebuild Kits, Repair & Replacement NP241 Transfer Case Parts & Rebuild Kits Starting in 1987, the NP241 transfer case was factory installed in four-wheel-drive vehicles from Dodge, GM and Jeep. It has earned a reputation as being reliably solid and a definite improvement over the NP203 transfer case that it replaced.