420FA not shifting (sigh) update, Shifts fine with the headlights on

[jeepwm69 7,605]

I didn't hear from Rapid Revolutions immediately, so I ordered a different speedo healer from Reduction Boss, which goes directly on the speed sensor instead of being wired into the speed sensor wiring next to the ECU.  This one is a bit cheaper than the model I got from Rapid Revolutions.

 

Naturally, as soon as I ordered the different speedo healer, I heard back from Rapid Revolutions, and they have emailed me several times since with troubleshooting advice.  They are convinced that I have a corroded plug somewhere that is causing the issue, since their shift module LED is still lit up.  I'm guessing that I will find what they say is true....eventually.  In the meantime, since it was too late to cancel the Reduction Boss healer, I'll remove the Rapid Revolutions module, hook wires back up in stock configuration, and then plug in the Reduction Boss unit and see if there's a change.  If not, then I'll know that there is another issue somewhere.  If it works, I'll know it was the module.

 

Of course, if it ends up being an issue elsewhere, one of my buddies has 2 of these DCT Ranchers for his kids so I'll be able to talk his son into a GR, and thus be able to use the "extra" shift module on his Rancher.😁

 

I was pleasantly surprised at the time Kevin at Rapid Revolutions spent sending me several emails instead of just trying to sell me another module. 

 

1st email

The autoshift modules are a sealed unit so there isn't anyway to repair

them.  However I would recommend doing a few tests on your power source.

  These units are very sensitive to fluctuations in voltage or poor power

connections.  Especially if it was working great then started to work

poorly.  Generally its almost always the frame ground or something along

those lines is slightly corroded.  The factory components will work even

with a pulsating 12volt signal which is quite impressive on the Honda

engineers.  We found this on a Rincon once where the ground was so

corroded it would shift manually without the autoshift but not with it

installed.  Using a Power probe is how we found the issue as the power

probes are very sensitive and showed us the power source we were tied

into was fluctuating in voltage.

 

2nd email

If the LED is lighting up and it stopped working after sitting I would
really be digging into other components.  The autoshift pretty much
works or its dead no led.  Its quite over built.  The factory sensors
one could be dead and not the other.  It would be enough to let it shift
but may give an issue when trying to go into 4x4.  The sensors are
supposed to match speed when the 4x4 switch is flipped before it will
try to engage the actuator.  The grounds and corroded connections can
wreak havoc on stuff.

The LED can be solid if its on a high point of the sensor coincidentally
or one of the sensors is stuck saying its on tooth of the gear all the
time.

The factory ECU can deal with messed up sensors but the Autoshift needs
to see a signal to output a signal so if it outputs jiberish the factory
ECU doesn't understand jiberish.
 

3rd email

 

With your description of issues I think there is definitely a corroded
connector somewhere.  Have you inspected the underside of the fuse box? 
I've seen it lots of times where the wires are still connected but the
corrosion is so heavy that they are only holding on by a thread.  So
voltage will get through for testing but no real amperage.

Way too coincidental with the other unrelated issues happening like the
fuel injection relay.  I don't think the autoshift has been damaged or
anything pretty sure its good you just gotta find the electrical
gremlin.  The autoshift only works when the systems are all in perfect
working order pretty much.

Thanks
Hopefully that helps.

 

 

[jeepwm69 7,605]

So update on this. Got the reduction boss healer in today. Disconnected the rapid revolutions module and hooked up the new one.

 

Take off and it shifts in auto...until 3rd, then it won’t upshift anymore.

 

Shifts 1–5 in ESP mode just fine. 

 

So looks like I do have some other issue involved here. I’ll have to dig into it maybe this weekend

[jeepwm69 7,605]

On 9/9/2021 at 6:47 PM, jeepwm69 said:

So update on this. Got the reduction boss healer in today. Disconnected the rapid revolutions module and hooked up the new one.

 

Take off and it shifts in auto...until 3rd, then it won’t upshift anymore.

 

Shifts 1–5 in ESP mode just fine. 

 

So looks like I do have some other issue involved here. I’ll have to dig into it maybe this weekend

 

So in true Jeep ADD fashion, this got pulled under the shed and I haven't messed with it in almost a year! 

 

I did drive it out to the duck hole the other day and it now shifts 1-4 in auto mode, but won't go into 5th in auto mode.

 

Shifts fine 1-5 in ESP.

 

Dang thing is possessed!

 

I did pick up a new speed sensor, shaved it down, and installed it, just to make sure that the speed sensor on the rear wasn't the problem.  No change.

 

At this point I'm trying to decide if I want to pull the gear reduction, put it back to stock, or just sell it like it is.  My back yard looks like a junkyard and the toddler has killed my wrench time, so don't have much time to work on all this stuff anymore.  When she gets a little older I'll put her to work helping me, so temporary situation with little/no wrench time.