Is there a way to make the 42RLE overdrive switch stay off by default?

[AndyG]

With OD on, transmission shifts way too soon into OD.
With OD off, transmission shifts way too soon into 3rd.
What idiot setup these shift points and why didn't Jeep come out with a TCM or PCM update to fix them?

The mod is in the how to section now

 

[Bro0214]

fireman3 on another forum:

42RLE overdrive solution

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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. View attachment 221887

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 View attachment 221888

Hi
Thanks for the write up
I’m curious
I have two LJ’s with automatic
I would like to do this mod
I was wondering why you used the light blue and orange wire , terminal 2-4
I took my switch apart to confirm
When depressed terminal 1 (ground) black is connected to terminal 2 (pcm sensing wire dark green )
Terminal 3 is the od indicator light dark blue, terminal 4 is the dash light orange
If I am reading this right you are connecting terminal 2&4 together via the relay when the vehicle is in reverse
Why wouldn’t you connect terminal 1& 2 ??

 

[jjvw]

Hi
Thanks for the write up
I’m curious
I have two LJ’s with automatic
I would like to do this mod
I was wondering why you used the light blue and orange wire , terminal 2-4
I took my switch apart to confirm
When depressed terminal 1 (ground) black is connected to terminal 2 (pcm sensing wire dark green )
Terminal 3 is the od indicator light dark blue, terminal 4 is the dash light orange
If I am reading this right you are connecting terminal 2&4 together via the relay when the vehicle is in reverse
Why wouldn’t you connect terminal 1& 2 ??

View attachment 595219

View attachment 595220

Save yourself the
effort. Just poke
the OD off button with
Your finger when you shift
Out of park.

 

[MillAlien]

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.

Thanks for restating that...I knew that the OD disable switch did two things and that it matters when you enable the disable, but I couldn;t remember what or why. I routinely disable on engine start as part of my start-up procedure, but now remembering that in doing so I'm actually disabing the disable.

That thing is a friggin' pain. It would have been much better if the OD was just off unless selected for highway driving. It's like having somebody jabbing me in the ribs and whispering that I shouldn't have gotten the 42RLE.

 

[NskLJ]

Thanks for restating that...I knew that the OD disable switch did two things and that it matters when you enable the disable, but I couldn;t remember what or why. I routinely disable on engine start as part of my start-up procedure, but now remembering that in doing so I'm actually disabing the disable.

That thing is a friggin' pain. It would have been much better if the OD was just off unless selected for highway driving. It's like having somebody jabbing me in the ribs and whispering that I shouldn't have gotten the 42RLE.

You could probably wire up an auto start stop eliminating module to do this. I have one in my F150 and works flawlessly. It sends the signal after startup to disable and then the switch works normally

 

[jjvw]

Thanks for restating that...I knew that the OD disable switch did two things and that it matters when you enable the disable, but I couldn;t remember what or why. I routinely disable on engine start as part of my start-up procedure, but now remembering that in doing so I'm actually disabing the disable.

That thing is a friggin' pain. It would have been much better if the OD was just off unless selected for highway driving. It's like having somebody jabbing me in the ribs and whispering that I shouldn't have gotten the 42RLE.

Something is missing in this analysis. I will often switch between OD on/off when I am fluctuating between 45ish and highway speeds. I do not notice any difference in the transmission behavior other than the usage of 4th gear and the overall differences in the shift points resulting from OD being on or off.

All of this is part of why I think this particular switch mod is dumb because it only saves me one button action that only occurs at startup.

 

[Bro0214]

Save yourself the
effort. Just poke
the OD off button with
Your finger when you shift
Out of park.

I have no issue doing that, it is trying to teach my better half to do it
Would like to just make it automatic

Something is missing in this analysis. I will often switch between OD on/off when I am fluctuating between 45ish and highway speeds. I do not notice any difference in the transmission behavior other than the usage of 4th gear and the overall differences in the shift points resulting from OD being on or off.

All of this is part of why I think this particular switch mod is dumb because it only saves me one button action the only occurs at startup.

The reason is my better half always forgets to push it at startup

 

[jjvw]

...


The reason is my better half always forgets to push it at startup

Then push it later when you notice something. You are using the button other times no matter what, which is why this is a stupid modification.

Your better half can figure it out if it matters enough.

 

[JMT]

I have no issue doing that, it is trying to teach my better half to do it
Would like to just make it automatic


The reason is my better half always forgets to push it at startup

@jjvw is just saying it is not a one time push of the button.