I've had my 92 f-350 7.3 idi since 2009 and the trans has never been quite right. It had around 2-3k on a complete rebuild. It was prone to going into safe mode every now and again. One day I replaced the ip and the truck got a major power increase I guess because the old pump was worn out. It ran and shifted awesome the first time I hit the pedal and then it has been shifting like its in safe mode ever since but no flashing od light.

I have replaced all the sensors, the tps is set dead on 1.1v and is completely within range. I have swapped in two different psom modules and properly programmed them for my tire size. All to no avail. The only code I have ever had consistently is a low vss signal.

The cruise control won't work either and never has since I've owned the truck. I assume because the cruise module nor the PCM is recieving a proper signal from the psom.

The only other thing I can think of is an internal problem causing excessive line pressure. Possibly in the solenoid block or the accumulator.

It shifts after 2k no matter how hard I am on the go pedal. Most of the time I have to back off of the pedal or it will not shift until its way up ther in rpms. It also has a tendency to neutral out every now and then between gears, usually at wot. Then every once in a while it shifts like its supposed to for a shift or two here and there.

I like having an auto but if I can't figure this out soon I'm going to fix it with a zf! This harsh shifting has caused all kinds of other problems including my cross pin falling out of the rear diff!

 

The problem is the VSS signal. Until you fix that the trans won't shift right.

 

I'll break out the diagrams and do some testing then. I'm looking into getting a breakout box to make this testing easier. It has got to be the wiring after the psom. I have a steady speedometer and a good vss sensor.

I also forgot to mention the fluid used to get burnt very quick and lose its bright color. It has stayed nice and fresh since it jacked up the line pressure. That's kinda why I've left it alone for two years. Anyhow I do appreciate the advise of a former engineer!

 

Where is the RABS module? That's the only thing I have yet to check/ swap out.

 

Well I found the rabs module.. Took out the glovebox and it was just hanging there because someone has ripped it out of the mounts.. And it has been opened up already.. Does anyone have a pin out diagram for the rabs module?