Transmission wiring diagrams please

When accelerating gearbox goes through all the gears but as soon as the car reaches eighty kmph the lock up torque converter engages. It is like changing from third to fifth. Goes like a dog after eighty unless you have your foot on the floor. Is there a way to manually control the lock up by a separate switch? The overdrive off switch drops it back to third gear. It would be nice to be able to use fourth gear without lock up on a slight hill.