It is located under the drivers fender in the very front corner behind the battery. They hide it pretty good.

 

sorry to but in but is the computer only used for the tranny

 

Yes, the comp is used to control the trans, grid heaters, wait to start, water in fuel, low fuel. But the computer has really no effect on the running performance of the motor.

Now someone correct me if I'm wrong but that is how I have understood it.

 

I know that I tried adjusting the TPS, replaced the VSS and everything short of replacing the computer and still no OD in mine. I went ahead and wired in a switch and OD works. Although when i was replacing the tranny pan with a deep pan I pinched the OD solenoid wire and when I tried to engage OD it fried the wiring inside the tranny. I had to get a new solenoid assembly and replace it. Now I have OD again via my switch, but still haven't had the time to get around to checking out the computer. But everything else on my truck does work, charging, grid heaters, although I haven't tried the cruise and such, the vacuum hoses are all rotted so those need replaced before any of that will work. But my understanding is that via the sensors, the computer regulates partial throttle shifts for OD and such. As well as cold engine behavior until it's heated up.