Choctaw

I've now joined the ranks of the not having over drive for a time. My situation was probably not typical and it cascaded into an additional electrical issue. About 4 weeks ago, I was arriving at home when the truck simply quit 30 feet from the gate. After getting things situated it turns out the culprit was a blown fusible link. After repairing that problem, it soon became apparent that I had no overdrive.

I examined the various posts pointing out the the TPS, VSS, solenoid, and other causes for loss of OD, and of course the shop manual. After eliminating everything else, the solenoid was the last possibility that could be the culprit. So I acquired a new solenoid, dropped the pan, pulled the filter, to discover the real cause......A short circuited wire. Apparently the last owner changed the transmission fluid and clamped the solenoid wires between the valve body and the filter. Given the vibrations the hummin' cummins puts out, it was only a matter of time before insulation on a wire was skinned. When I inspected where the wire was cut, I could see the positive lead(the skinned one) was balled, obviously a short and thus the cause of my previous fusible link issue.

So for anyone else having the loss of OD, here's another possibility to add to your check list. I'm still going to add the potentiometer next week though,as a sidenote I did find the weatherblock plugs there for that at diesel manor.