2021 4xe Rubicon sting grey
How rad would a 4xe meet-up in Big Bear be this summer?
Anyone know if Mopar has been lobbied for this nonsense to change? Or how we go about petitioning for a change? I wouldn’t have bought the 4xe if I knew, though I do really enjoy it. Thanks!It occurs to me that there are at least 2 work around options. Probably more...
When regeared the drivetrain sensor outputs don't match the PCM expected values [cannot be changed ATM]. To the best of my knowledge there are 5 tone rings that measure speed [for this discussion] . 1 in the transfer case or transmission and 4 at the wheel hubs 1 placed at each corner.
The tone ring pickup measures speed and turns it into a variable frequency increasing with rotation speed.
Since the transfer case tone ring is before the differentials it's output wouldn't be affected by a regear. The wheel hubs however are after the ring and pinion. Therefore after a regear the wheel hubs now report a different and now [out of range] speed or frequency.
1. Tone ring tooth count at the wheel hubs and or transfer case. Modifying the tooth count could bring the values back into range expected by the PCM.
2. Use a raspberry pi to intercept the wheel hub tone ring frequency and report a corrected value back onto the canbus.
3. Petition Mopar to allow for regear up to 5.38 this would be the lowest ratio possible for a Dana 44 and anything lower is not particularly worthwhile.
Both options 1 and 2 would not correct the speedo but I believe the JL tazer could be used to change the tire size and perhaps get close. I personally don't care if it is off. A GPS speedo is ok with me.
Option 2 could be particularly unstable but super easy to install as all you would need to do is create a daughter board capable of adding input and output connectors (for vehicle plugs) and writing the code capable of translating corrected frequency.
That being said... the raspberry pi could crash or a loss of power (to the raspberry pi) could cause the PCM to freak out and might shut down systems or the whole vehicle.
Whereas option 1 will always be stable just like the OEM design. Replacing tone rings is a PITA but entirely doable.
Hell, even limited to 5.13 gears gets us pretty close. For stock at 4.11 that's 4.1 rotations of the driveshaft for every 1 rotation of the wheel. 5.13 would be really close to 1 complete additional driveshaft rotation.
Both routes could very well be a marketable item... I would be inclined to pay up to $2500 in additional costs to get my tons and 40's.
Of course there are additional costs to add steering assist, driveshafts, new wheels, yada yada yada.
Any additional thoughts or comments?
What would you be willing to live with or pay to get your tons?
My $.02 I yield the floor...
Ok, let's explore the hydro assist! Is this for a 4xe or a gas model?Funny you should say mods….. hydro assist going on now. And skid playes. Getting mods to take on isn’t the issue unfortunately ….
Definitely thirsty! 91 octane all day long...Yup that’s going to need a stop at the ol gas station or two ….. but should be a sweet ride!!!!! Congrats
Perhaps we should get as many people as possible to connect with jeep cares regarding this limitation to show the demand is real.So I'm just checking in on this thread as I haven't been on it in awhile b/c there haven't been any new developments on the regear issue. I have started a conversation with FCA/Stellantis on the limit they have built in to the brain on the 4xe's. Alexander with the Stellantis Customer Care team seems to be sympathetic to the issue. He has sent my correspondence to one of his (top) mangers and I'm hoping there's an easy fix and that it won't just be brushed off.
Since these Jeeps have the potential to be some of the most capable wheelers that have hit the highway with the lower CG and instant torque I think it would be crazy to hobble these with a stupid coding problem. I could see their sales numbers getting hit hard if the off-road guys turned their backs to the 4xe. I'm sure the R&D on these were extensive and not cheap. Hope they make it right soon.
I volunteer to lend a re-geared 4xe. I am running 5.13s and have been for a year. No and, no cruise control, no regen, no stability.@Bodell
I was reading through the forums since I have 2 4xe Rubi's and wanted to regear one, but as you already found out, Tazer doesn't support it and just updated the website to say 4.11 is the lowest ratio supported now, not 4.50.
Superchips doesn't support the 4xe at all - same issues, people tried it and all sorts of problems
I asked ECRI what they were capable of, same issue - 4.50 max - but ECRI has had some experience with spoofing the ecu on JK's for ford axle swaps
You are the only person I found so far who has already regeared.
Kevin at ECRI has offered to send a unit for testing if you want to work with him - all experimental of course so no guarantees. I'm a computer engineer by trade and asked him some questions about how the ESC system actually calculates the lookup for the wheel sensors and transmission sensors, and if the ESC computers could be tricked into allowing everything to work within the 4.50 limit. Speedo would be wrong since it's an ECU hard limit, but he wants to try some things out.
If you still have the 4xe geared and sitting, let me know if you are interested and I'll put you in contact.
Is there anyone else here that is having the same issue that has 4.56 or 4.88 already in their 4xe?
I just joined so can't PM - send me a message with contact info for anyone interested.
I do want to reiterate ... Kevin said it was a "long-shot idea of tricking a sensor" and MAYBE fix the issue. But the only way he can program and test is with a 4xe that is already regeared.
If anyone has any suggestions to address the re-gear issue please share them.
min my book it’s pretty ridiculous that as a brand, Jeep hobbles their electrified future like this. Of course 4xe Jeeps will be modified in increasing numbers as years go by. That’s how this works. When I re-geared no one knew the programmers would not work. And after nearly a year nothing has happened.
This would not be okay for any other business and it frankly represents a deeply frustrating issue for me.