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Discussion Starter · #1 ·
Is anyone else having issues overheating in 4WD? We started going off roading (narrow dirt road, a few small creeks to cross, no big rocks) yesterday and after a few miles in 4WD I started getting messages that the transmission was overheating and I needed to step on the brakes or drive over 5mph. Neither helped, nor did letting the jeep sit for awhile. You can also hear the engine getting really loud trying to cool itself unsuccessfully. I had to drive a few minutes at a time until I could get back to 2WD which drove fine. Not cool!
 

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I’ve been reading several posts about this. One off-road expert I talked to said a lot of times, it is caused by being in 4lo for too long when 4hi can be used.
 

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Discussion Starter · #4 ·
Initially I was in 4WD high when I had the issue. I switched to low and had the same problem. Initially 4WD low wouldn't go over 3 mph and then kicked in but it was still over heating constantly. I was never going over 10mph in either mode.
 

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I’ve been reading several posts about this. One off-road expert I talked to said a lot of times, it is caused by being in 4lo for too long when 4hi can be used.
That is interesting. I would've expected 4Lo to be better for keeping things cool. My F250 Diesel truck stays cooler when backing up a heavy trailer in 4Lo compared to 4Hi. That is a totally different situation though....
 

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That is interesting. I would've expected 4Lo to be better for keeping things cool. My F250 Diesel truck stays cooler when backing up a heavy trailer in 4Lo compared to 4Hi. That is a totally different situation though....
Yeah, that's what I would have thought too. I've seen other Jeeps overheat in 4 Hi, but are fine in 4 Lo.
 

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Maybe the ICE Jeeps cool better in 4LO since the fan has more air flow due to higher RPMs where the 4xe's fan is electric so the lower range just causes the engine to run faster without any extra air flow?
 

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Discussion Starter · #8 ·
The 4WD High Auto kept switching to hybrid and I think that's part of the issue. I'd force it to eSave and it would work a little better. It kept switching back to hybrid though as I shifted around. I was pretty upset about driving on narrow roads on the side of a cliff and having a brand new Jeep's transmission overheating and having to stop on the side to wait for it to cool. In hindsight it wish I'd taken a few photos of the Settings but I was more worried about the road giving way under me while I was waiting for the damn thing to cool down.
 

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The 4WD High Auto kept switching to hybrid and I think that's part of the issue. I'd force it to eSave and it would work a little better. It kept switching back to hybrid though as I shifted around. I was pretty upset about driving on narrow roads on the side of a cliff and having a brand new Jeep's transmission overheating and having to stop on the side to wait for it to cool. In hindsight it wish I'd taken a few photos of the Settings but I was more worried about the road giving way under me while I was waiting for the damn thing to cool down.
What were temps outside??
 

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Discussion Starter · #10 ·
It was 80-85. We were near Custer, Idaho. Started at 6500 ft elevation, peaked at 8000 ft elevation.
 

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i guess the oil film of the 5W-30 getting to thin , special in summer heat + off road. same for the tranny. i use a sip of motorkote with oil change and filter over 30 years + a sip for the tranny as well . works out for me. not tryed Lucas yet but can be good for motor oils with low vis as well. and mobile 1 oils. the 4xe engine works always hard not as easy as a 3000 pound sports car. so reducing friction = reducing heat. oil changes + oil filter + airfilter after 5000 miles . the first oil change + oil filter after a "break in " i do is after 500 - 1000 miles.
after i blow up two bmw engines $$$$ when i was young and know everything ..lol.. i try to take care of maintenance. don't trust at all the service , check before and after them. they like to "skip" oil changes or doing it wrong ! wrong ? yes they filled the the oil between the plastic cover and engine head. so always check it your self. and hey there is no oil is good for 20-50000 miles..lol.

cheers
 

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2021 Jeep Wrangler Rubicon 4xe / 2015 Jeep Wrangler Willys JKU / 2005 Jeep Wrangler Sport
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When we were in Colorado a couple weeks back climbing an old 4x4 trail from about 8000ft up to just shy of 12000ft and had it in 4WD high about half the way up when I noticed the transmission temp was up to about 240 degrees F. Stopped and put the transfer case into 4WD low and the transmission temperature began to drop back down to 200 degrees F without any further issues. It was crazy warm outside, in the high 90's at 8000ft and 75 at 12000ft.
 

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I’ve been reading several posts about this. One off-road expert I talked to said a lot of times, it is caused by being in 4lo for too long when 4hi can be used.
Is it the engine where heat becomes a problem or the trans in 4LO? If it's a high friction road using 4LO may not be an option.

I was in sand with 4PT and had the transmission get hot. But I managed to cool it down while I walked the trail looking for a good line to take.
 

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Discussion Starter · #15 ·
When we were in Colorado a couple weeks back climbing an old 4x4 trail from about 8000ft up to just shy of 12000ft and had it in 4WD high about half the way up when I noticed the transmission temp was up to about 240 degrees F. Stopped and put the transfer case into 4WD low and the transmission temperature began to drop back down to 200 degrees F without any further issues. It was crazy warm outside, in the high 90's at 8000ft and 75 at 12000ft.
This sounds like the same issue. I was in 4WD High for the majority of it as well though the outside temp wasn't quite as hot it was in the mid 80's.
 

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This sounds like the same issue. I was in 4WD High for the majority of it as well though the outside temp wasn't quite as hot it was in the mid 80's.
Both my 2005 TJ and my 2015 JKU are manual 6-speeds and I've never had any overheating transmission issues, that being said they are both significantly lighter than the 4xe. The 4xe didn't seem to need to be in 4WD low (both my TJ & JKU would have definitely needed to be in 4WD low on this climb) and I only put it in 4WD low when I saw the transmission temperature.
I wonder if being in the 4WD auto mode with the transfer case puts extra strain on the transmission for some reason.
 

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We offroaded with the 4xe two days this past weekend with no issues.

4 low the entire time in a pack of 11 vehicles and some severe hills and obstacles.

Sent from my SM-G998U using Tapatalk
 

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I was quite disappointed to learn Jeep adapted a traditional automatic transmission for the 4xe vs the excellent PowerSplit unit found in many other PHEVs (including the Pacifica). There must have been too many compromises with the 4x4 requirements.

However, they did get rid of the torque converter so that should help reduce the heat output. I wonder what is causing the transmission to get so hot? The friction plates must be activated with pulse width modulation vs on/off so that would be one possible thing that could cause over hearing at slow speed?
 

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The 4WD High Auto kept switching to hybrid and I think that's part of the issue. I'd force it to eSave and it would work a little better. It kept switching back to hybrid though as I shifted around. I was pretty upset about driving on narrow roads on the side of a cliff and having a brand new Jeep's transmission overheating and having to stop on the side to wait for it to cool. In hindsight it wish I'd taken a few photos of the Settings but I was more worried about the road giving way under me while I was waiting for the damn thing to cool down.
Are you still experiencing concerns at this time, dcmeagle? If so, send our team a private message and we can discuss.

Kate
Jeep Cares
 
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Discussion Starter · #20 ·
Are you still experiencing concerns at this time, dcmeagle? If so, send our team a private message and we can discuss.

Kate
Jeep Cares
We are on a 13 day trip and abandoned doing any more jeeping for the rest of our trip as the overheating left us in a dangerous situation. I'll send you a private message, thanks.
 
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