Finicky behavior on ZF transmission with temp change?

[dgeist]

Not sure if it's a JLUD-specific issue (perhaps shared with the 392 folks?) but this afternoon, I got a "Service Transmission" message on the dash after being out of the vehicle for a few hours. There was no CEL (onscreen or via OBD) but the menu functions were all disabled. So, I drove down to the local dealer (about 5 miles) and kept an eye/ear out for anything strange. Nada. After shutting off the engine, I restarted it and the message went away. I scrolled through all the diagnostic screens and the only thing that looked out of sorts was the trans temp (at only 105F after driving five miles...). The tech at the dealer pulled the persistent codes and only found one even remotely relevant (error shifting into park...) but no idea how long it had been there. Total mileage on the vehicle is only about 24k miles, so I'm WAY early on any expected service items with the transmission.

Temps dropped quite a bit in the past day, down from the mid-70s to mid-30s, but other than that, nothing changed in driving patterns or use. Although I don't recall looking at it specifically, my memory says the temps should have been closer to 200F after driving a few miles on a warm engine.

In any case, I drove home and it STILL only showed 115F on the display for trans temp after the 5 mile return.

Are the trans cooling lines on the JLUD run in such a way that they'd be impacted by something like a stuck thermostat? Engine temps seemed fine... What about the temp sensor on the ZF. Could I have damaged it somehow? Is it visible from beneath?

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[BDinTX]

My bet is on the battery nearing end of life. When mine started going at 3 years and 55k miles I started getting water in fuel messages.

 

[dgeist]

My bet is on the battery nearing end of life. When mine started going at 3 years and 55k miles I started getting water in fuel messages.

That would be something... since both (batteries) were replaced fresh off the lot just over 2 years ago after the vehicle sat on the lot waiting for recall parts for 6 months. I wonder if it's worth finally doing the start/stop battery delete mod?

 

[BDinTX]

Ya even if only temporarily to troubleshoot. This came in handy for me:

https://www.amazon.com/gp/aw/d/B01MT4583U?psc=1&ref=ppx_pop_mob_b_asin_title

Once it’s hooked up you can see what your voltage drops to when you start the engine.

 

[JeepinPete]

I've had my Jeep for 5 years now. Every once in awhile some odd error pops up and goes away on the next start never to show up again. Unless it was shifting funny or the error message persisted I wouldn't worry about it.

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