JLUR decelerating while coasting in **2H**... help?

[BernJLUR]

I think your issue is two fold. First could be the steep gearing of the 8 speed auto and 4.10’s. Secondly, it’s possible that you are having the surging idle issue which is extremely noticeable during deceleration at those speeds. There is a TSB that addresses the surging as well as the noisy cooling fan. Have you noticed an abnormally loud engine cooling fan noise while at idle with the AC turned all the way to its coldest and highest fan speed setting?

Hi Shenanigans. I read threads about people complaining about the cooling fan at coldest. Mine is louder than my previous JKs for sure, but the comments I read about other drivers commenting about its noise or describing it as a jet liner going overhead, that doesn’t fit. It’s louder than last generation, but not ridiculously like some had to fight through. I wonder if it’s your first fold scenario plus my inexperience above 3.XX gearing.

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[BernJLUR]

Btw I might have missed this part, but are you driving 4H on pavement?

Shoot! Dumb response. Meant 2H. Yes. Typical daily driver mode. Tested 4H and 4L at dealer and worked, then back to 2H. Sorry - that must’ve been confusing.

 

[Rubicon4Life]

Hi all. I’ve had three automatic JK/Us and I drive countless rental vehicles each year. I just purchased my 2019 factory build JLUR three weeks ago. Shortly after leaving the lot, I noticed the brakes felt a little bit sticky and grabby (technical mechanic terms ) at under 20 mph coming to a stop. Shortly later, I realized that the vehicle seems to decelerate even when coasting at that speed without touching the brake pedal. It kind of feels like when cruise control slows you down when you’re a few mph over the designated speed, or like driving with two feet where the left foot is always gently and inconsistently riding the brake. It’s subtle, but it’s constant and I’ve never experienced it with any other Wrangler or rental.

I’ve searched the forums and found nothing. But I don’t even know what terms to search for. I’m hoping my fellow Jeepers can guide me a bit so I don’t sound like a lunatic when I consult with my dealership. This is not a Jeep thing. I’ve been in Jeep things since 2010 (1992 if you count a CJ7 manual). This is a my brand new JLUR thing.

Any ideas? Thanks in advance for your guidance!

I have a 2019 Rubicon that I picked up at the end of May with the 3.6. I feel the exact same thing. Not sure if its a problem or just the way this vehicle is designed. I came from a 2011 Sahara Unlimited that was a complete POS. I'm interested to see what other 2019 Rubicon owners with the 3.6 say. Ironically enough my vehicle is in the shop right now for a replacement front grill and my soft top rattling. I didn't even think to bring this issue up because I assumed it was normal. Have you heard anything else?

 

[COSJL]

I don't know if I have the same symptoms as OP, but at slow speeds I do feel what I assumed was too much engine braking. Sometimes the transmission shifts a bit rough 4-3-2 as well. These two combined can make for an unpleasant driving in stop and go situations. I'm hoping the shifts improve with miles.

 

[Arterius2]

I don't know if I have the same symptoms as OP, but at slow speeds I do feel what I assumed was too much engine braking. Sometimes the transmission shifts a bit rough 4-3-2 as well. These two combined can make for an unpleasant driving in stop and go situations. I'm hoping the shifts improve with miles.

there is a TCM update to be flashed at the dealers to make the shifting a bit smoother as well.

 

[#4Jeep 1st Wrangler]

In got the same shifting. It is a normal condition with this transmission. Low speeds, it will downshift and feels like it's holding the vehicle back. I'm still in the auto repair business, every one I've driven does this....JL models
(8 speed transmission , common with 4.10 gears etc....) I assume that you have a Rubicon or Moab with the higher gets gear ratio?

 

[COSJL]

there is a TCM update to be flashed at the dealers to make the shifting a bit smoother as well.

Thanks you. Any chance there is a TSB/update number that I can tell the dealer? I am assuming they will just say mine has latest software.

 

[COSJL]

In got the same shifting. It is a normal condition with this transmission. Low speeds, it will downshift and feels like it's holding the vehicle back. I'm still in the auto repair business, every one I've driven does this....JL models
(8 speed transmission , common with 4.10 gears etc....) I assume that you have a Rubicon or Moab with the higher gets gear ratio?

Thanks for the input. You are right, I am not hoping the engine braking to change - nature of the beast I guess. I do have a Rubi. I do want to smooth out the transmission shifting though.

 

[Arterius2]

Thanks you. Any chance there is a TSB/update number that I can tell the dealer? I am assuming they will just say mine has latest software.

Not sure, I have to check my service bill when I get home, but according to some on this forum, they were able to get it flashed as well, I guess later 2019 models don't need or have an update yet.
https://www.jlwranglerforums.com/forum/threads/pcm-tcm-update.28401/

 

[Arrowhead]

In got the same shifting. It is a normal condition with this transmission. Low speeds, it will downshift and feels like it's holding the vehicle back. I'm still in the auto repair business, every one I've driven does this....JL models
(8 speed transmission , common with 4.10 gears etc....) I assume that you have a Rubicon or Moab with the higher gets gear ratio?

This ^^^^^

It's totally normal, no need for service, no diagnostics required, your brakes are fine. Most cars tend to freewheel when you let off the gas but they programmed the 8spd a little different. I actually lets you control your speed with the throttle pedal kind of like a manual.

 

[Durango]

In got the same shifting. It is a normal condition with this transmission. Low speeds, it will downshift and feels like it's holding the vehicle back. I'm still in the auto repair business, every one I've driven does this....JL models
(8 speed transmission , common with 4.10 gears etc....) I assume that you have a Rubicon or Moab with the higher gets gear ratio?

Every 7 or 8 or more speed tranny FCA vehicle I've owned in the past couple years does this - I've just assumed it was part of getting better mileage somehow, or? Regardless, it's handy when driving in the mountains to have the tranny downshift without having to consciously do so.

 

[BernJLUR]

In got the same shifting. It is a normal condition with this transmission. Low speeds, it will downshift and feels like it's holding the vehicle back. I'm still in the auto repair business, every one I've driven does this....JL models
(8 speed transmission , common with 4.10 gears etc....) I assume that you have a Rubicon or Moab with the higher gets gear ratio?

Yes. JLU Rubicon with the 4.10 gears. This is good and bad. Good that it's a normal thing. Bad that I don't like the driveability coming to stop signs and lights and traffic jams.

 

[Rubicon4Life]

This is great info and definitely clears things up for me. I have a 2019 Rubicon that I purchased in May of 2019, 2 months ago.

 

[JeepCares]

Hi all. I’ve had three automatic JK/Us and I drive countless rental vehicles each year. I just purchased my 2019 factory build JLUR three weeks ago. Shortly after leaving the lot, I noticed the brakes felt a little bit sticky and grabby (technical mechanic terms ) at under 20 mph coming to a stop. Shortly later, I realized that the vehicle seems to decelerate even when coasting at that speed without touching the brake pedal. It kind of feels like when cruise control slows you down when you’re a few mph over the designated speed, or like driving with two feet where the left foot is always gently and inconsistently riding the brake. It’s subtle, but it’s constant and I’ve never experienced it with any other Wrangler or rental.

I’ve searched the forums and found nothing. But I don’t even know what terms to search for. I’m hoping my fellow Jeepers can guide me a bit so I don’t sound like a lunatic when I consult with my dealership. This is not a Jeep thing. I’ve been in Jeep things since 2010 (1992 if you count a CJ7 manual). This is a my brand new JLUR thing.

Any ideas? Thanks in advance for your guidance!

Hey BernJLUR,

If you do decide to move forward with visiting your dealer in regard to this concern, please feel free to send us a private message. We would be more than happy to have your concerns formally documented as well as provide you with an additional layer of assistance by connecting you with a Case Specialist who can work alongside your dealer.

Mark
Jeep Social Care Specialist

 

[WXman]

I don't know if I have the same symptoms as OP, but at slow speeds I do feel what I assumed was too much engine braking. Sometimes the transmission shifts a bit rough 4-3-2 as well. These two combined can make for an unpleasant driving in stop and go situations. I'm hoping the shifts improve with miles.

Yes, the trans. and engine braking is WAYYYYYY too aggressive for a vehicle of this type. For what it's worth, my JT Gladiator is the same way. It's extremely annoying.

Also, if you accelerate hard from a stop, say, 80% throttle, and then quickly go to 40% throttle, it'll hang up in the gear it was in and the RPMs will keep screaming. It won't upshift. VERY annoying.

As usual, FCA has a way of taking world-class ZF transmissions and ruining them with in-house programming.

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