No Overdrive
 

I have a 93 Dakota 5.2 automatic 4x4. When I bought the truck a couple months ago I had no overdrive and was getting codes 12 15 21 and 55. I replaced the O2 sensor and the VSS and adjusted the TV cable and still get no overdrive. Fluid level is good doesn't smell burnt and I only get code 12 and 55 now but still no overdrive? The tranny seems to shift fine other wise and now down shifts when you stomp on it but no OD. The OD switch does light up when I push it to turn OD off so I am assuming it is function as it should. Any Ideas would be appreciated.

torque lockup work?

anyway the oveerdrive is electronically controlled so either bad wiring or the ground trigger wire,OR the solenoid itself is dead inside tranny

I'm not sure if the lock up is occuring or not i didn't noticed anything after it shifted into 3rd. Any suggestions on where to start checking wiring?

Are you sure you have a good VSS? Does cruise control work? Sometimes new parts are defective.

Before you go chasing wiring harness gremlins, I would check the OD solenoid itself. Verify failure with a 12 volt test lamp.

Check to make sure you haven't blown the overdrive circuit fuse. If you have indeed blown a fuse, then you will want to figure out what's shorted by attacking with the test lamp and voltmeter so you dont keep blowing fuses.

The VSS is really important for the 3-4 overdrive upshift, but torque converter lockup and OD also depends on other inputs to the engine computer. If you have any reason to suspect that your throttle position sensor, MAP sensor, or coolant sensor are going bad, then that could be part of the problem, as those are all going to determine lockup and shift timing. But let's not get ahead of ourselves, let's worry about the solenoid first.

First off thanks for the response. Second all tho I am very mechanically inclined and have worked on cars my whole life and even worked in a garage and had my Pa. inspection license, Electrical has never be my forte. Wiring diagrams confuse the heck out of me. That said.

I assume the vss is working because I am no longer getting the code 15 for the vss after replacing it. the tps, map and coolant sensors have all been replaced and I checked the fuse and all tho it was good I replaced it anyway. The cruise doesn't work. As stated the tranny shifts fine other wise after hooking up the TV cable on the tranny end and adjusting it at the throttle body, also the tranny seems to stumble slightly at about 52 like it wants to kick into over drive but doesn't. or maybe that's lock up trying to kick in not sure. I have read a ton of threads on here regard this issue and I can follow test instructions but haven't seen anything about testing the od sensor.
Thanks again for the response.

On my 96 (V8,) it was the fan clutch relay in the relay/fuse box near the battery. I also didn't have 1st gear.

Easy to check, btw. Switch out one of the other relays (like the a/c) and see if it makes any difference. You can get replacement relays for practically nothing at any wrecking yard that has Dodge products.

Hope this helps.

Thanks for the response. 93's don't have a fan clutch relay, They have a blank spot for it but nothing there to plug the relay into. I read an older post about this earlier and ran right out to check it but no go.

if your up for it..

On the driver side of the transmission above the oil pan is a connector with 3 wires in it and it points straight up. I need you to test the dark blue wire with the key on and there should be battery voltage there. If there is can you bare the orange/light green wire(it might be orange/white) and tie a long wire into it long enough to reach inside the truck. Then you will need to hook your red lead on your multimeter to positve and hook the black lead to that wire you ran up in the cab. You will have to run a wire from the battery positive to the inside of the cab and hook it to the red lead. The PCM provides a ground to that wire when it wants it to shift into o/d. So, take it for a drive up to 60mph and see if the voltmeter shows battery volts when you are at that speed.

you can do the same for the other wire on oposite side of the blue wire aswell which would be the torque lockup .. they are both ground wires, this is what i had done to test tranmission and solenoids before ripping apart oilpan ..

I Have company coming for dinner in a bit but will get to this a little later this afternoon and let you know the results. Thanks