I have a 91 Plymouth Grand Voyager with A-604 Tranny. recently started going into limp mode when accelerating, going from 3rd to 4th. Changed oil/filter (with ATF+4) changed input and output speed sensors. Had codes from TCM read: 54 which my manual says is "internal Problem" so what's next? A friend told me that the e-clip holding the OD clutch disks could be broken. yes? If so is this a major jobb to fixx? could the sol pack somehow misbehave and fool the TCM into thinking it is this code?