My overdrive quit working again...........this time it just stopped with no pre-warnings. The speedometer needle still works perfectly fine. What I'd like to know: Is there a way to wire up a manual switch to engage overdrive (4th gear)? I realize there are more things that can contribute to this problem (TPS, etc)............but what about manually controling overdrive? Any ideas?

 

Yes you can wire it to be manual. I have a rocker switch mounted on the end of my console that controls the o.d.. It was almost 2 years ago when I did it so I don't remember what the wire colors were. I like it because i'm lazy and lean over and prop up on the console anyways so it's right at my hand to flip the switch. I'd tell ya what color wires and how I did it but one of my guys has that truck hauling his kids horses to the rodeo. I also have the gear vendor o.d. on an old style dimmer switch so I can drop 2 gears if needed.
Good luck with it because it can be done.

 

I would definately like to know how this can be done. If anyone knows where to tap into the wires and what colors, let me know.

 

Just put a toggle switch on it. I don't think the colors matter. Look at the trans on the driverside, your looking for the plug that goes strait up and down with 2 wires. One is a ground and one is hot just ground one wire to the chassis and hook the other one to a switch and away you go. I think there is a write up in the sticky about it.

 

I read somewhere you can replace the shift handle with a
2nd gen handle which has a button on the end for that purpose.

 

Absolutely that is in the sticky also and it does look slick. I think BC did the write up if I remember correctly.

 

The dark blue wire is hot when the key is on. Tap into the other wire. Ground it when the trans is in 3rd and you have OD. A refinement on this method is a pressure switch in the governor pressure test port, there's a writeup in the sticky about doing it that way.

 

Sounds fairly simple to rig up a switch. I currently have the later model Dodge O/D shifter installed, maybe I'll use that as my switching device.

I'm thinking that somehow a wire or electronic component is the culprit for my OD not working. Honestly, I can't see the 4th gear clutch pack inside just failing all of a sudden without some kind of slippage before going out. The O/D just quit........no pre warning signs.

 

That's a momentary switch like the dash button. You are going to need a toggle.

 

OK, I crawled under the truck and found the vertical switch on the driver's side of the transmission. The 2 wires were dark blue & orange. I tested the dark blue wire, seems to be "hot" when the key is on. What about the orange wire? Is the orange wire just a path to ground? This factory switch in the transmission is normally open? So........it's a pressure switch? When a certain pressure is met, then it closes the switch and allows O/D to engage? Just trying to understand how it works.

 

Those wires go to the OD solenoid, which controls a valve in the trans to shift you into OD. The PCM applies ground to the orange wire when it decides you need OD.

 

Hhhmmm.........so put a switch between the orange wire or blue wire? Or do I put the switch between the orange and dark blue? I just don't want to fry my PCM. Working on this as we speak.......

 

he says to tap into the wire that is NOT blue and run it to ground.

 

Ok, I understand........

Anyway, I hooked up a switch on the orange/green striped wire coming off the OD soleniod plug. I ran one side of the switch to a known ground. Test drove the truck........got it into 3rd gear and then hit the switch on, nothing! Tried it again and again......nothing. When I got home I checked continuity with my meter on all the wires I have ran........good. So, what might else cause my OD not to work any longer? Could the OD solenoid be bad?

 

Did you leave the plug off the solenoid and just ground the orange wire?

Might seem like a stupid question but you wouldn't be the first to screw it up. Plug has to be on the solenoid so it gets power and ground.