Quote Originally Posted by billygraves View Post
First I would like to say is this. The XDF files are NOT what actually came from the calibration. They are reverse engineered and they have mistakes. Addresses and verbiage. Scaling of variables can be off. You see this in what you are describing and have missed how the trans pressures are set in the calibration.
The calibration value 0 to 90 is actually a PTS. Pressure Torque Signal. The pressure the force motor makes on the Pressure regulator line up. Plus the area and the spring pressure in each selector range except in Reverse where the Rev boost compounds the pressure to a higher value. So you say the trans runs at 200 PSI but the cal is 90. 90 PTS not PSI. This is where the reverse engineered XDF's have you at a disadvantage. I have not sat and compared each value in these reverse engineered files and won't. It takes to much time and there are many calibrations missing.
You can have a 4L80-E in Drive Range and the calibration at the given place is 90 PTS. The Trans Line Pressure in PSI will be aprox 170 PSI measured. If it is in Reverse it is much higher as you can easily see in a hydraulic flow chart. This will help explain what PTS is and PSI are when you are calibrating the transmission. I hope this make sense.
Which IMO is the reason you should really attach a hydraulic pressure gauge when calibrating the line pressure tables. With the plethora of stock and aftermarket pressure regulators, springs, field adjusted EPC solenoids, etc it is entirely possible to have too little or too much pressure.