Overdrive/3rd gear shift problem

[Flightsimmer]

I have been having a problem with "downshifting" into 3rd gear with the "overdrive" button located on the gear shift lever. Particularly when the oil temps have cooled down over night. It is very bad now that the colder weather is here. I have a Banks "Stinger Plus" turbo kit and their "PAC" brake installed. This shifting issue has cropped up in the last year approximately and has gotten to the point that pulling our 32ft 5th wheel is kinda tricky . Specifically when downshifting is needed on a hill or coming to a stop at an intersection as engaging the brake is discouraged while in "OD". With temp. being the issue I wondered if it was in the transmission fluid. Truck has about 128,000 miles. I replaced the transmission fluids at 105,000 miles. Sometimes if the button is held "in" and the shift lever wiggled the light indicating the downshift has occurred will blink intermittently.Eventually as things"warm" up it will stay engaged. '99 F-250 Power-stroke/diesel, auto trans.

[Mark Kovalsky]

I think you are saying when you press the OD OFF button it does not always turn off the overdrive. I'm not sure that's what you're asking.....

If that is your problem, start by removing the plastic cover from the steering column. Carefully inspect the wires where they enter the shifter handle. They are probably rubbed through or broken inside the insulation. Either fix the wires or get a new shifter handle for about $50.