TREMEC TKX 5-Speed PerfectFit™ Kits for AMC are the simplest and most cost-effective way to convert to a modern overdrive with proven case machining techniques and compact shifters that provide the best fit and shift quality available. Silver Sport Transmissions CNC machines the TREMEC TKX case and tailhousing to streamline the case as much as possible and also move the shifter position into the factory-correct location for a PerfectFit.