No Overdrive

JackDonkey

Registered
I cannot shift into overdrive, the o/d off light stays on constantly. It seemed like a problem with the switch at first (like it would kick me out and I would just hit the button or fiddle with the area i reconnected the wires), and I had fixed the switch at one time. So I took the console off and dissconnected the switch and closed the circuit on the transmission side of the disconnected connector and nothing. The light refused to go out or blink or anything. Is it possible that I didn't completely retighten one of the harnesses inside the transmission after I removed to take off the valve body when I did the shift kit mods? I was going to just drop it off again today and check on it, but I got too lazy. I'm going to end up doing that anyway but if anyone else as any suggestions of what to look for that would great thank you.

Dustin
 
RE: No Overdrive

Test the switch. With the harness unplugged, and a ohm-meter at the disconnected harness plug on the switch side, momentarily depress the switch. With the button pushed, you should have continuity. Release the button and you should have an open circuit. The momentary contact switch signals the PCM in a flip-flop fashion to allow or disallow shifting into O/D with the default at starting the car is O/D allowed.

You could test the remainder of the circuit by momentarily shorting across the harness plug on the downstream side of the switch harness with the car running. This would simulate the switch action. Start the car and O/D light should be off. Briefly short across the plug and O/D light should be on(O/D disallowed). Short across briefly again and it should revert back off(O/D allowed).

A flashing O/D light is a sign of something else.
 
RE: No Overdrive

well that's the thing, the last time I could momentarily short the switch and that doesn't want to work anymore. So I'll tell if I find anything out tomorrow when I work on it... fortunatly I have the wekk off of work. I could always drive my motorcycle to work though which is what I usually do, 55 mpg vs. 22 mpg I go for the 55
 
RE: No Overdrive

I took the pan off today and I didn't see any loose wires, I wiggled them a little to make sure they were connected and things of that nature. So I then put the pan back on, if you guys have anything I should look for that would be great, I'm going to read up in the helm manual and see if they have anything. If not I make sure to take pictures and write up a bunch of notes on how hard it is to install a T-45 in a mark viii

dustin
 
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