Overdrive
Thread Starter
Drifting
Joined: Feb 2013
Posts: 1,451
Likes: 48
Overdrive
Hello,
I have 1984 4 plus 3. I have been trying to get the overdrive to work. I hot wired the overdrive and it worked. I found out that with the switch on no power was coming up the green wire and going to the display. But, just today the overdrive lights on the display went on. They shut when I went into first gear and shut on hard acceleration. The overdrive did not engage. I shut it on and off and the RPM stayed the same. A couple of months ago I filled the OD with new fluid.
Any ideas?
Thank you
Joe
I have 1984 4 plus 3. I have been trying to get the overdrive to work. I hot wired the overdrive and it worked. I found out that with the switch on no power was coming up the green wire and going to the display. But, just today the overdrive lights on the display went on. They shut when I went into first gear and shut on hard acceleration. The overdrive did not engage. I shut it on and off and the RPM stayed the same. A couple of months ago I filled the OD with new fluid.
Any ideas?
Thank you
Joe
Oil Producer
Joined: Apr 2014
Posts: 9,349
Likes: 2,726
Hello,
I have 1984 4 plus 3. I have been trying to get the overdrive to work. I hot wired the overdrive and it worked. I found out that with the switch on no power was coming up the green wire and going to the display. But, just today the overdrive lights on the display went on. They shut when I went into first gear and shut on hard acceleration. The overdrive did not engage. I shut it on and off and the RPM stayed the same. A couple of months ago I filled the OD with new fluid.
Any ideas?
Thank you
Joe
I have 1984 4 plus 3. I have been trying to get the overdrive to work. I hot wired the overdrive and it worked. I found out that with the switch on no power was coming up the green wire and going to the display. But, just today the overdrive lights on the display went on. They shut when I went into first gear and shut on hard acceleration. The overdrive did not engage. I shut it on and off and the RPM stayed the same. A couple of months ago I filled the OD with new fluid.
Any ideas?
Thank you
Joe
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The ECM controls whether the OD unit is engaged or not. When you push the OD button it ASKS the ECM to turn on OD. Then the ECM decides whether or not to actually turn it on. There are several things the ECM looks for before it will turn on OD. I have an auto trans so it's not something I know a lot about, but I do know that the coolant temperature has to be above some number before it will turn on OD. I believe the ECM will turn on an OD light on the dash when it turns on the OD unit. You will have to check your FSM wiring diagram to see how that works.
Race Director
Joined: Apr 2003
Posts: 17,697
Likes: 1,666
From: moraga ca
One of the first mods I did when I bought my 84 was to bypass the computer and rewire the od unit so the switch on the console controlled it's activation. I used it as a 5th gear on the freeway.
