You know..on others makes this is a sign of loose engine mounts. The shifter gate is affixed to the frame and when the engine moves it can pop out of gear..as well as put undue stresses on everything connected to the frame that is also attached to a loose engine...like muffler mounts, cables, brackets, head pipes..and other things..like drivelines...ect. At least it's something to check. CFM is well knows for loose bolts.