Went for my first long road trip this weekend with only a ATV in the bed. At freeway speeds (65-75) in 4th gear when the TQ Converter is locked and between 1/2 - 3/4 throttle the transmission starts shake or shutter. If I gave it full throttle it would smooth up or if i just gave it 1/4 throttle or so it would be fine. Doesn't do this in 4th before the tq locks or with the OD off and in third. Any transmission guys out there with any thoughts? Low pressure, time for new tq converter, OD going out?