because the vast majority of time I run with overdrive switched off anyone know of a way to make OD OFF the default and overdrive on switched? Basically reverse of what it is.
Is there a way to make the 42RLE overdrive switch off by default?
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It's a momentary switch so you'd need to add in something that will momentarily close the circuit each time the Jeep powers on.
Anything is possible with a big enough hammer.So it is possible? Last time I asked everyone told me it wasn’t possible
It's technically not impossible to do but it would require a complex latching circuit whose design is above the paygrade of anyone I'm aware of here. At least not without some study and electrical circuit design ability. A simple on-off or momentary contact switch wouldn't be enough.
The overdrive switch controls not only whether or not the transmission shifts into 4th gear (overdrive) but also in which gear torque converter clutch lock up occurs.
If you turn overdrive off before the 2-3 shift occurs, the TCC will lock and then unlock as soon as the transmission shifts into 3rd.
It’s a bit of a hassle to have to hit the switch after the 2-3 shift occurs but this will dramatically extend the life of the transmission.
If you turn overdrive off before the 2-3 shift occurs, the TCC will lock and then unlock as soon as the transmission shifts into 3rd.
It’s a bit of a hassle to have to hit the switch after the 2-3 shift occurs but this will dramatically extend the life of the transmission.
Of course it is, it provides a momentary ground connection to toggle the OD on & off. That's why I said nothing like it is the fix for what the OP wants to do.
You just need something like this but set to only push the OD button as you start the Jeep.
I saw that somewhere a few days ago and it just cracked me up. When I was first learning electronics in the early 60's I built a few "do-nothing" boxes that included cool circuitry but which did absolutely nothing useful except entertain me like that. My first do-nothing box just had six randomly blinking lights that kinda looked like early computers with their many flashing lights. It was cool! Years after I built it and had kinda forgotten it, I came home after four years in the military and rediscovered it in the back of my closet.... still flashing away lol.
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fireman3 on another forum:
42RLE overdrive solution
Been searching for a solution to shut the OD off in my LJ instead of having to flip the switch every time I start it.
Have read a few suggestions but never found anyone who actually did it so today I decided that I'd give it a try.
This solution works great and leaves your overdrive off switch functioning like factory, the only difference is that the overdrive is now in the off position normally instead of the normally on position.
For anyone who wants to do this it is simple if you have a little mechanical experience.
What I did was use a relay which is hooked into my backup lights to shut the OD off. Since you have to go past the reverse position to put your Jeep into Drive, the backup lights always blink on for a split second and that is what turns the OD off.
I spliced into the backup lights by using the white and lt green wire under the c drivers side kick panel cover.
Then I spliced into the green and orange wires on the back of the OD shut off switch.
I ran these wires to a relay that I tucked behind the glove box, added a ground wire, and it works !
If I want overdrive, I simply flip the original switch and presto, I have overdrive.
The light in the switch still works so you can see if it is in OD or not.
I believe the relay was wired like this:
Ground-85
BU light wire-86
Orange wire-87
Green wire-30
The numbers are usually printed on the little relays
Hope this helps someone
42RLE overdrive solution
Been searching for a solution to shut the OD off in my LJ instead of having to flip the switch every time I start it.
Have read a few suggestions but never found anyone who actually did it so today I decided that I'd give it a try.
This solution works great and leaves your overdrive off switch functioning like factory, the only difference is that the overdrive is now in the off position normally instead of the normally on position.
For anyone who wants to do this it is simple if you have a little mechanical experience.
What I did was use a relay which is hooked into my backup lights to shut the OD off. Since you have to go past the reverse position to put your Jeep into Drive, the backup lights always blink on for a split second and that is what turns the OD off.
I spliced into the backup lights by using the white and lt green wire under the c drivers side kick panel cover.
Then I spliced into the green and orange wires on the back of the OD shut off switch.
I ran these wires to a relay that I tucked behind the glove box, added a ground wire, and it works !
If I want overdrive, I simply flip the original switch and presto, I have overdrive.
The light in the switch still works so you can see if it is in OD or not.
I believe the relay was wired like this:
Ground-85
BU light wire-86
Orange wire-87
Green wire-30
The numbers are usually printed on the little relays
Hope this helps someone
Brianj5600
TJ Expert
How about using the starter wire in the column? Use a diode to prevent the OD switch from powering the starter.
So, you start the Jeep, and move the shifter out of park, either going into reverse or into drive is enough to activate the 'OD Off' button. But, if you put the Jeep in Park and then back to drive again without ever shutting it off, it will activate the switch again, turning the OD back on, right?
I think you are onto something here, but I wonder if there is just a different 12v source to trigger off of, other than the reverse lights.
This is a fun experiment!
I think you are onto something here, but I wonder if there is just a different 12v source to trigger off of, other than the reverse lights.
This is a fun experiment!
rouxbicon
TJ Enthusiast
Seems like this would pulse it twice, (D>R>P>R>D) so OD should be set right back to off, no?
This is how I did it on my Dodge Ram. The ignition starter wire to a relay that was in parallel to the OEM O/D switch wires. The stock switch was still functional to turn it back on or off. No diode needed. Easy way to check is to hold down the O/D switch while starting. Does it turn it off?
I would need to test it.....but how about something like this. Tap off of the starter solenoid wire and run it to a relay. Have a ground on the common leg of the relay and the energized leg going to the transmission OD switch wire. Everytime you start the Jeep it would provide a ground to the OD switch wire and when you let the key go Run, the ground would be removed.
There are two potential issues with this setup though.
1. It would provide a ground the whole time the starter is engaged. Not exactly sure this would "trigger" the OD off.
2. The transition from "Start" to "Run", not sure if this would interrupt the cycle for switching the OD off.
Thoughts?
There are two potential issues with this setup though.
1. It would provide a ground the whole time the starter is engaged. Not exactly sure this would "trigger" the OD off.
2. The transition from "Start" to "Run", not sure if this would interrupt the cycle for switching the OD off.
Thoughts?
I am waiting for one of you guys to figure it out and do a write-up so that once mr 42RLE swap is complete I can do this mod 
Chop, chop, let’s get to tinkering!
Chop, chop, let’s get to tinkering!
BLUF: What about using the PAC TR-7 module commonly used to activate ECT Mode in Tacomas?
In addition to an LJ, I have an auto 3rd Gen Tacoma. The stock shift points aren't great on the truck, but you can fix this problem by hitting the "ECT Mode" button, which is sort of like enabling sport mode. To get the benefits of ECT mode, you have to hit the button every time you start the vehicle - sound familiar? A lot of Tacoma guys use the PAC TR-7 module to automatically activate ECT mode on startup. Instead of your finger hitting the button, the module completes a circuit when it receives an "ignition on" signal (in this case, from the cigarette lighter).
I wonder if there's a way to do something similar with the O/D button on 42RLE-equipped jeeps? The "how to" for the auto ECT mod is located here: https://www.tacomaworld.com/threads/ect-mod-on-all-the-time.456373/ . The module was cheap and really easy to wire up in the Tacoma...any thoughts on a jeep application?
In addition to an LJ, I have an auto 3rd Gen Tacoma. The stock shift points aren't great on the truck, but you can fix this problem by hitting the "ECT Mode" button, which is sort of like enabling sport mode. To get the benefits of ECT mode, you have to hit the button every time you start the vehicle - sound familiar? A lot of Tacoma guys use the PAC TR-7 module to automatically activate ECT mode on startup. Instead of your finger hitting the button, the module completes a circuit when it receives an "ignition on" signal (in this case, from the cigarette lighter).
I wonder if there's a way to do something similar with the O/D button on 42RLE-equipped jeeps? The "how to" for the auto ECT mod is located here: https://www.tacomaworld.com/threads/ect-mod-on-all-the-time.456373/ . The module was cheap and really easy to wire up in the Tacoma...any thoughts on a jeep application?
Rubicon John
TJ Enthusiast
I was under the impression that one can feel the tq converter locking when the rpms drop while cruising in 3rd. (Almost feels like a shift in to 4th) Is this true? If so, mine does that no matter when I turn the OD off.