possibly a theft recovery and it has a replacement column from an earlier year
which would explain the lack of button

 

There is no button on that shifter. That is just strange..... On the earlier trucks, it was up by the cup holder, along with the fog light switch. (sport models) But, that spot isn't even there any more. I am real curious what happened to yours.

 

Yeah, maybe its time to trace some wires in the column.

 

did some looking around and it looks like people with the old a518 (1st gen i'm guessing) were modifying those transmissions to where they could manually control their O/D. one of the options was to get a shift column off a 2nd gen that had the O/D button on the shifter. I wonder if your truck was a donor to one. you might start by looking under the dash on drivers side to see if there was any sighs of rewiring. maybe a relay (might even say "overdrive" on it, or a toggle switch that was spliced in somewhere to bypass the overdrive switch.

 

Thanks for response.

Im thinking along the same lines but i dont know why anyone would go to the trouble of doing that. I will check today to see if the **** is a screw on or not. if so I would imagine If there are wires there I can re route and wire in my own on off switch on the dash for the overdrive on off. I hope this is the case.
Can anyone shed some light on the code itself?

po751 overdrive switch low
In blue is found on the web...

P0751 DODGE Description Over Drive (O/D) switch value has not changed for over 5 minutes

Possible causes Faulty overdrive off switch
- Overdrive off switch harness or connectors
- Overdrive off switch circuit is open or shorted

What does this mean? When is the code detected?
- The P0751 code is detected when the Over Drive (O/D) switch value has not changed for over 5 minutes

Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Transmission will not shift gears.

P0751 DODGE Description Over Drive (O/D) switch value has not changed for over 5 minutes

Read more: https://www.autocodes.com/p0751_dodge.html

Im confused as to why if the overdrive switch is operator controlled, the truck computer would sense a problem if it has not been switched within five minutes?
why would i be switching my overdrive on and off within five minutes? I wouldn't use it to turn it off unless i was hauling or bed was heavy loaded. Which i certainly wouldn't be doing every five minutes on and off...
This to me implies that the truck controls the overdrive on or off which I have never heard of ...what the hell am I missing here?
Has NO ONE heard of having no overdrive switch in this yer and model?

Thanks again any and everyone.
Cheers

 

I'm not sure about the meaning on that code either and haven't heard of no O/d button on that truck.


Was wondering about the shifting on the truck though. Have you had normal O/d operation in the past and has anything changed with it engaging lately?

 

I have found no signs of rewiring or any other macgyvery anywhere outside the steering coloumn. Days off coming up I am going to be opening up the coloumn...info I find to follow.

 

Truck is about a month new to me. I have had far from normal overdrive operation as I cannot turn it on and off.
As far as shifting, it Shifts fine through the gears while driving. I have driven a ton of vehicles and this feels like it is in overdrive as it doesnt seem to cranking rpms when on the highway and cruising. I can feel it shifitng well through the range.
I have had the overdrive OFF light on the dash come on once bys itself a few weeks ago. The definition of the code is a confusing one for sure. Why the hell would it need a change in status signal within five minutes? I am not new to wrenching on vehicles. I am a maintenance and repair tech for a guy with too many farms and too many vehicles and too many people that dont know how to use the equipment. I have seen and solved some very strange things since working here for the last 4 years. This one is just weird though. If the switch was bypassed, and a non stock gear selector put on why would it randomly turn on and off by itself the one time. I also have some very strange vacuum line issues that I am trying to sort out but thats a diffo day and a diffo thread.

 

Maybe, during the startup sequence, the PCM cycles it momentarily??? Meaning you might also have a bad OD solenoid.

Just shootin' from the hip here...

 

According to the wiring diagrams, the O/D Off switch is a normally open, momentary switch. Which kinda makes that code meaningless...... unless it is shorted closed?