I have a 02 F250 Super Duty XLT with a triton V8 with a automatic transmission . and when I shift into reverse after driving for a while the starter engages . It does not happen all the time . If i start up the truck and shift through or into reverse it doesn't happen . the only time it happens is when i've been driving for awhile and want to back up or park it will only do it once or twice after each drive so trying to get it to happen while in the shop is almost impossible . could this be caused by the transmission range sensor . I just had the code P0705(transmission range sensor , A circuit input ) come on but the problem has been happening for a few weeks before that code came up .

 

You might want to shoot Mark Kovalsky a pm. He is a big help when it comes to tranny issues.

Ford Truck Enthusiasts Forums - View Profile: Mark Kovalsky

 

This isn't a transmission problem, it's external to the driveline.

Most likely, it's an internal short in the TRS or its associated wiring.

 

Had the same issue. Like SHO89 said its going to be the TRS. (Trans range sensor) it's the only place start and reverse come together. It's a quick fix to swap the part and solved the issue for me. Buy the ford one! The car quest one I installed failed in less than a year.

 

Without the engine running and key on you should be able to get it to do it by back and forth with the shifter..The switch would almost have had to come apart for that to happen.
Check wires and cable underneath for chafing.

 

Have to agree with ProjectSHO, the TRS would be the first place to start.

 

You'll notice I said the "TRS and it associated wiring".

Keep that in mind as the problem may well be external to the switch.