Automatic Transmission Failure

[LS7]

Haven’t posted here for a while, but I do keep checking in to keep up to date with what’s going on.
Last week, we were in the back country near Moab (Chicken Corners, Lockhart Basin, Lockhart Canyon, etc.) we had a great, but occasionally challenging trip. Upon returning to Moab, the town was crazy. It took almost an hour in stop and go traffic to get through town. Midway through town, while rolling about 3-4 miles an hour, my 2018 Rubicon (V6 motor) slammed itself into park. It felt like someone hit me from behind. I could move the gear selector (indicator lights would flash), but could not get it out of park. Error messages said “service electronic traction control“, ”front airbag deployed”, and ”service transmission”. Called a wrecker, put the transfer case in neutral to free the wheels so the Jeep could be loaded onto a trailer and transported to Salt Lake City ($1,000 tow bill—yikes). My dealer said initial inspection suggestS a faulty valve body, but he wants their ”transmission expert” to inspect it and he has a 1-2 day backlog. I shudder to think what we would have done if the failure would have happened during the first two miles of the Lockhart Basin trail. It would have taken a helicopter to get it out. I‘M sure the dealer will get my Jeep repaired, but I’ve lost confidence in taking my Jeep into the back country.
Has anyone experienced similar problems? What repairs we’re required? Did you have a reoccurrence of the problem? Thanks in advance for your reply?

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[LS7]

Update: Dealership says the problem was caused by a faulty valve body. One is on order and due to arrive next week. Anyone know what a valve body is and why it would fail at 11,000 miles? Thanks.

 

[LS7]

I answered the first part of my question, “What is a valve body?” I cut and pasted this from Cartreatments.com:

“All automatic transmission systems have a valve body which serves as the “brain” of the transmission.

There are dozens of various passages and channels within the valve body which direct the flow of pressurized hydraulic fluid to different valves in order to activate the right clutch pack or band and shift to the most appropriate gear based on the current driving situation.

Think of each channel as a tumbler on a lock which has to perfectly line up so transmission fluid is directed where it should.

The valves that make up the valve body each serve a different purpose and their names reflect what they do. For example, the valve body has a 2-3 shift valve which is responsible for up shifting from 2nd gear to 3rd gear.

And if there’s going to be a downshift from 4th gear to 3rd gear, then the 4-3 shift valve would be responsible for that.”

Don‘t you just love the internet?

 

[keithg2101215]

The valve body is an electronic and hydraulic controller for the transmission.

https://en.wikipedia.org/wiki/ZF_8HP_transmission

PS the 8 speed transmissions are dirt cheap in the used part market.

 

[LS7]

Thanks. Much more complete and relevant answer than I found.

 

[keithg2101215]

Haven’t posted here for a while, but I do keep checking in to keep up to date with what’s going on.
Last week, we were in the back country near Moab (Chicken Corners, Lockhart Basin, Lockhart Canyon, etc.) we had a great, but occasionally challenging trip. Upon returning to Moab, the town was crazy. It took almost an hour in stop and go traffic to get through town. Midway through town, while rolling about 3-4 miles an hour, my 2018 Rubicon (V6 motor) slammed itself into park. It felt like someone hit me from behind. I could move the gear selector (indicator lights would flash), but could not get it out of park. Error messages said “service electronic traction control“, ”front airbag deployed”, and ”service transmission”. Called a wrecker, put the transfer case in neutral to free the wheels so the Jeep could be loaded onto a trailer and transported to Salt Lake City ($1,000 tow bill—yikes). My dealer said initial inspection suggestS a faulty valve body, but he wants their ”transmission expert” to inspect it and he has a 1-2 day backlog. I shudder to think what we would have done if the failure would have happened during the first two miles of the Lockhart Basin trail. It would have taken a helicopter to get it out. I‘M sure the dealer will get my Jeep repaired, but I’ve lost confidence in taking my Jeep into the back country.
Has anyone experienced similar problems? What repairs we’re required? Did you have a reoccurrence of the problem? Thanks in advance for your reply?

Who paid for the tow bill?

 

[LS7]

I paid and have submitted for reimbursement from FCA. It will be interesting to see how that goes.

 

[LS7]

Update:. Dealer replaced the valve body under warranty, and found no other problems. Jeep seems to be running fine. The dealer said that they have had no other incidents of a valve body failure on a JL, and judging by the lack of replys to this thread, neither have other forum members.

 

[laroo]

I missed your initial post, but the wife's 2020 had the same issue late last year at around 2,000 miles. Valve body replaced, no issues since. There are definitely other cases of this happening.

https://www.jlwranglerforums.com/forum/threads/2020-wrangler-transmission-failed.45483/

 

[LostWoods]

It's a ZF 8-speed... probably the most prevalent transmission in existence right now and it's extremely well regarded in other applications. That includes everything from BMW and Audi to Aston Martin and Bentley to the Supra and Hellcat. I know these are FCA vehicles but if there's one thing you can write off as rare defects, it's the physical transmission.

 

[laroo]

It's a ZF 8-speed... probably the most prevalent transmission in existence right now and it's extremely well regarded in other applications. That includes everything from BMW and Audi to Aston Martin and Bentley to the Supra and Hellcat. I know these are FCA vehicles but if there's one thing you can write off as rare defects, it's the physical transmission.

I don't disagree with you at all. I'm just letting LS7 know he's not completely alone with this issue.

 

[LS7]

I missed your initial post, but the wife's 2020 had the same issue late last year at around 2,000 miles. Valve body replaced, no issues since. There are definitely other cases of this happening.

https://www.jlwranglerforums.com/forum/threads/2020-wrangler-transmission-failed.45483/

I missed this thread when I made my initial post. Thanks for letting me know about it. I’m planning a trip back to Moab mid-November. Based on the experience of a few others, I think I’ll drive my Jeep as much as possible before heading off-road. Where we are plan to go would be a very difficult recovery if I experienced another transmission failure.

 

[Geezpnd]

Hi there! I’m in the same situation with my new JL. How’s it running now?

 

[LS7]

Hi there! I’m in the same situation with my new JL. How’s it running now?

I've not had any problems since the valve body was replaced. I’ve been back to Moab 3 times and Kanab once, doing trails rated moderate and difficult, plus 6-700 highway miles for each trip.

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