Hey guys new here, anyways I got a new to me 99 Dakota 318 and it has 80 thousand miles with a rebuilt transmission and the pcm was replaced. Drove smoothly and awesome. About a week after that the O/D light came on the dash and wouldn't go away even tapping the overdrive button. Then sometimes It randomly flashes off and on and will go away if I wiggle the gear selector a little. It will do this when the truck is cold and hot. And the trans fluid isn't low either. I figured maybe It could be a simple fix if not I'll take it back to the transmission shop

 

is it jumping out of 4th when it's doing this? If so, sounds like a shorted wire in the switch harness. It's a braided wire, pink and white as I recall, runs through the shift lever and into the steering column before joining the main harness.

Use a small screw driver, pop the end bezel off the shift lever, and the button should fall out. You can clip one of the wires off and tape it to eliminate a bad switch, but if they are shorted in the column, it will still occur. You can take the clamshell off the steering column to investigate further.

 

Yes it does jump out of 4th when it does this, I'm only driving city so I'm only going 50 so the rpms aren't rising too high. The overdrive dash button will flash off and on while cruising like 15 mph in the neighborhood so this does seem like it would be a lose connection like you were saying. Thank you very much

 

I know this is old but i hate how people never update. I have a similar issue but just the pcm was replaced with a reman, and at times the OD light would come one randomly. On mine i found the reman pcm to be the problem. If i move any of the connectors on the pcm in a upward motion the light will go on and off but if someone pushes the center one in and i try to move any of the others the light does not come on. So it seems that something is flexing internally on the pcm board, I know this may not be everyone's fix as some will have wire issues or valve body issues but this is a weird one i have found