I have an old 1990 4 speed Auto in my R129 V8. It shifts fine both up and down. I have changed the fluid in the Torque Converter as well as in the box and changed the Filter. I have no problem at all with the shift quality but I would love to be able to get it into 4th at a lower speed or before 3000 RPM. Does anyone know if this is possible or does the box have to get to a certain hydraulic Pressure governed by RPM before it will shift to 4th?
