limeade

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Finally some common sense! Shifting at unsafe speeds (determined by the road condition) is never advisable. I've down shifted in my old muscle mopars on rainy roads and have fish tailed all over the place. Slippery conditions warrant more brain cells working and slowing down before drive train configuration changes.
Downshifting a transmission vs. engaging 4WD on slippery surfaces is two entirely different things with two entirely different outcomes. A sudden downshift of the transmission (especially at a speed where the gear downshifted into shouldn't have been selected) not only causes a rapid gain of RPM's, but also a sudden weight transfer which can and will cause a rear wheel drive car to fishtail. Engaging the transfer case from 2 Hi to 4 Hi at any speed doesn't cause any of this and therefore will not cause a vehicle to fishtail or break traction.





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RubiSc0tt

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This is strange. OP sounds like he didn't do anything wrong. I've got a 2019 JLUR on the KO2's and I've done this same thing on any of the multiple times heading to work during any one of the snowstorms we've had here (Upstate NY) in the past year or so. I've also done it in my past 2 Jeeps with MT's. Never really had a catastrophic failure like this. I have had a little slide BEFORE shifting into 4wH in all.
This sounds like it might be some kind of crazy "perfect storm" for an unusual failure. Curious what happens.

A note on dealers: I'm noticing a trend: If a dealer "can't replicate the issue", they just clear all codes and hand it back saying "let us know if it happens again" only to have the same thing occur and the same result at the dealer. This is pretty much all issues from the UConnect to something larger like this. Unless the vehicle is actually handicapped when it comes in, they sort of gloss over it. Big problem IMO, coming from a similar position in a different field. We see people clear an error every time and then it reoccurs and most don't think anything of it until something MAJOR happens. That's when a whole lot of uncomfortable questions get asked and people get fired. There are procedures in place to review all previous data and do some root cause analysis. Not really a commentary on dealers or even Jeeps- I just wish there was an easier solution on the dealer end. It would be nice to see what the techs are doing and have some sort of in depth analysis given, or the ability to actually TALK to the techs directly and show them. I've asked before and the Service writers usually block it.

I work on slightly more complex systems at work, so I'll try to trouble shoot through things and research stuff before going to a dealer, but dealers do not seem to care about any sort of diagnosis from the customer, regardless of experience. This is why I try to avoid dealers until all other options are exhausted.

Good luck OP. Make sure you cover all bases. Even if FCA is in the wrong, they won't go easily should it lead to court.
 
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sf5211

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Not sure why any of you think you can't/shouldn't shift on the fly on a slick surface. The 4WD system is designed exactly for that! Your front wheel/tire assembly are already turning and there is no sudden application of force causing someone to lose control if engaging 4 Hi in this manner.

I would think it HIGHLY improbable that an LSD rear differential would cause this loss of control when engaging 4 Hi. If it were truly that slippery, the LSD wouldn't even be effective. Now if he had a locker engaged (whether mechanical or selectable) and was in a curve and he suddenly added strong acceleration, the locker could then cause a loss of control due to the rear wheels turning at the same rate.

In the OP's case, it seems as if there was some mechanical malfunction which caused an unexpected lock up of something which then caused an irrecoverable loss of control, which was not driver error. This is supported by his previous problems and visit to the dealer service dept.

I have over 30 yrs. of driving in snow (from the mid-west, to Alaska, the northern plains states, to the Sierra Nevada's) and have always had a lever operated transfer case. I have and continue to engage 4 Hi when conditions warrant and sometimes this means while I'm already on a slick surface. I have done this at higher speeds and have never lost control due to engaging 4WD.

Just last week I was on a road trip from Billings, MT to Las Vegas, NV and encountered multiple snow storms and poor road conditions. Several times I went from to 2 Hi to 4 Hi at speeds between 65 - 70 mph and yes I know the manual states going into 4 Hi at 45 mph and under, but it will without issue. In my experience, the transfer case doesn't want to go into 4 Hi above 70 mph.
Hi Guy, I would actually slow down to the 45 mph to shift into 4Hi and then speed up to the desired speed.
Not because of road conditions, you’re a big boy and know how to drive. I say this because if you did shift in past 45 and say your transfer case blew out and the Jeep weren’t drivable, they’d be able to see your speed when you shifted by checking the Jeep’s computer.
I think a lot of folks don’t realize these modern vehicles can record everything. When I put my 2013 Isuzu work truck in for service, they give me a “vehicle health report”. It’s unbelievable what’s recorded, how many times I brake, top speeds, am I heavy on the gas pedal in short distances....
If someone is doing 45 in a 25 and gets into an accident with injuries and they tell the police they weren’t speeding or were hitting the brake when they really weren’t. The investigation would find out.
 

Roky

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Hey folks,

I bought my JLU Willy's in the summer of last year. I've started taking my Jeep up to my local mountain for snowboarding days. I used to live in upstate NY and I am used to variable road conditions. 3 weeks ago when I was using the 4WD system (in snow) it made an odd noise and the check engine light came on. It also seemed like it would not shift into higher gears. It showed a "Service Trans" in the console errors. Took it into the dealership and they returned it to me the next morning. The notes in the invoice said that per Chrysler protocol, they just cleared the codes and gave it back to me after test driving it and not seeing any check engine lights come back on. Told me if it happened again, then they would consider looking at fixes.

Yesterday I was driving the same drive back up to the mountain, the roads had a pretty mild amount of snow/slush mix so I decided to turn on my 4WD High. The second I shifted the transfer case it felt like my wheels locked up and the Jeep started to fishtail wildly. I tried to mange the movement but couldn't control it. The jeep bounced softly into the snow bank on the right shoulder and the my Willy's ROLLED onto the drivers side and I quickly climbed out. No glass broke, no airbags deployed, no injuries to me or anyone else (that's the good news).

The bad news is....WTF just happened?

IMG_4032.JPG


My Questions:

1. Has anyone else had an experience like this with their transfer case/4WD system!? I am extremely confident that I operated it correctly and the conditions were quite drive-able, I had little Hondas passing me with no problems at all.

2. It surprised me that the Jeep rolled with so little force and given the direction of the force (being mostly to the front right corner). I know Jeeps can roll, but this seemed a little gratuitous. Does this seem "expected" to you all?

Thanks for any insight or help, taking it back to the dealer next week.

Also in the notes from the service before this happened were a bunch of codes (again this is what they just cleared before returning to me):

"the codes that i found in the system reads:
TCM P0721-00 Output Shaft Speed Sensor Circuit Performance-Stored
TCM P0607-00 ECU Internal Performance-Stored
PCM U0418 Implausible Data Received From Brake System Control
Module 1 Stored
ABS U0402-00 Implausible Data Received From TCM-Stored
DTCM U0402-00 Implausible Data Received From TCM-Stored"
Hey Jess..... first off , glad you’re ok....after talking to my buddy that’s a lead mechanic at the dealership, those codes were to do with a possible problem that could cause a lock up. IMO , that’s your ace in the hole here moving forward. It sounds like you did everything right, and nothing out of the ordinary. Good luck brother, hope you get it sorted out.
 

22Mag

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My 4wd selector is very stiff, it's a 2020 Willy's also. I've never had a problem with it but I don't think it's suppose to be so hard to operate. Glad you were ok and the Willy's if fixable.
 

dgoodhue

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I have plenty of times shifted into 4WD at high speeds with incident in other on demand 4wd trucks. I wonder if the slippery conditions allowed the rear tires to be turn slower than the vehicle speeds when you shift in 4wd which caused the vehicle to slide. I suppose a faulty stabilities onto that applied the rear brakes could have cause this as well. You probably should steered into the slide and applied some power to correct it.
 

calemasters

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Mud tires and slick roads dont mix well. Ive seen it many times.
I have the OEM Falken M/T's off road tires on my Rubicon. This vehicle is very capable off road in dirt, mud, rocks, etc. but does not do well on snow and ice surfaces. The tires look very aggressive but with no siping, they are a let down in snow. Of course, for ice you need chains or studs. My JKR did not have the clearance for chains.
 
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rallydefault

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I have had a number of on road dangerous power losses and system issues while driving
Dude, I think it's time you get a new vehicle. Seriously. I will not stay with a vehicle that shuts off on me when I'm driving. Happened in my Renegade when I was pulling out of a shopping mall onto a crowded road. Thing just shut off. I was done.
 

word302

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During your transfer case shift from two wheel high into four wheel high, were you on the throttle or on the brakes? I am not sure what happens if the rear driveshaft speed is different than the front driveshaft speed while shifting from 2WH to 4WH since in 4WH both driveshafts have to rotate at the same speed.

Sometimes I wish my Rubicon had the full time automatic Selec-Trac® transfer case instead of the Rock-Trac NV241.
The front driveshaft doesn’t spin in 2wd. It doesn’t cause any problems.
 
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calemasters

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The front driveshaft doesn’t spin 2wd. It doesn’t cause any problems.
In 2WD, there is no torque to the front driveshaft from the transfer case. But when the front wheels are rotating, in the same direction, the drive shaft has to rotate.

When going straight, with no wheel spin, both drive shafts are rotating at the same speed. This is true in both 2WD and 4WD.

Edit: The above is true for JK's. Not for JL's with FAD.
 
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JDJeep85

JDJeep85

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Thanks for all the info and great suggestions all around folks. I was able to pull some codes from the Jeep yesterday and I got a a handful that appear to indicate clutch failures and electronic failures with the ABS system. Again, I'm not a tech (just looked them up online), but glad I have a copy of the codes pulled off. Some are also similar to the ones that appeared before this incident. Glad I pulled them too b/c I had planned to drive the Jeep to the dealer, but I think I'll have it towed given what already happened and that the severity of these codes looks high (which I guess makes sense). Thanks again everyone, we will see what happens next.
 

word302

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In 2WD, there is no torque to the front driveshaft from the transfer case. But when the front wheels are rotating, in the same direction, the drive shaft has to rotate.

When going straight, with no wheel spin, both drive shafts are rotating at the same speed. This is true in both 2WD and 4WD.
That is incorrect. The Jeeps have a front axle disconnect (FAD), which means little to no rotation on the front driveshaft in 2wd. In 2wd the spider gears are spinning but the ring and pinion are not.
 

Bikemobile

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In 2WD, there is no torque to the front driveshaft from the transfer case. But when the front wheels are rotating, in the same direction, the drive shaft has to rotate.

When going straight, with no wheel spin, both drive shafts are rotating at the same speed. This is true in both 2WD and 4WD.
if the front driveshaft rotates in 2wd then why add the cost and complications of the FAD? Front axle disconnect?
Full time 4wd (auto4wd) is and has been an option on rubicons in europe and now in the US.

The FAD was added on the JL for increased fuel economy and general reduction of NVH.
 

Bruce Willys

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My 4wd selector is very stiff, it's a 2020 Willy's also. I've never had a problem with it but I don't think it's suppose to be so hard to operate. Glad you were ok and the Willy's if fixable.
Mine was extremely stiff at first when my JL was new, so much so I was afraid I might break something forcing it. It's super easy to engage now, it took some time/usage to break in. It's smooth as butter now.
 

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