I have a 1991 c 1500 Silverado. Shifts in 1st, 2nd 3rd 4th/od on or b4 30 mph by lifting slightly on throttle but at 50 55 feels like it needs that one more shift. To bring the rpms back down then cruse on but wont do it. Also dont have passing gear after 4th. I have replace a new Governor, New Speed Sensor, New TV cable New fluid and filter. Dex. V1 Tried straight wiring the switch. Cut the three wires. Put 12 volts to the purple wire and tied the other 2 together. That way took out OD completely. Where it was getting od just at an around 30 mph. Can anyone tell me whats going on with this. Drove and shifted perfect for over a yr, All Help Appreciated.