AFAIK, Only Dodge used (past tense) the NV 5600 six speed. Ford used a ZF 6-speed, and GM used to use the NV4500 5-speed, it was almost the same as the Dodge unit, but did not have a synchronized reverse. Now, Dodge uses the Mercedes G56 transmission, and Ford and GM are strictly auto only. NV Gear went belly up a few years ago, and the transmission is no longer produced. According to the TDR forums, the MB transmission is excellent.