" Service Transmission" and Check Engine light.

[Mr.PoodlePants]

**Update. jeep home now. The cause of the symptoms below were resolved by the dealer, under warranty by replacing the transmission oil pressure sensor.

2021 stock 392. Just over 15,000 miles. I was gently mudding Sunday evening , the mud was just over the bumper. While moving forward and back in 4wLo with everything locked I got the Service Transmission message on the dash. After extracting myself from the hole, I pulled to the side, took some photos and then left. Upon leaving I soon realized the transmission was not upshifting. I stopped, shutdown and restarted and everything seemed fine. After the ride I hit the car wash and upon leaving I was unable to shift into Reverse. The lever in reverse but the R light would just blink and the Jeep would not move. I put it in Drive and had the same issue with it not shifting. Shut down, restart and went home fine... Next day after a couple attempts to drive I now see a pattern where when the jeep is started, Reverse will not work and Drive will not upshift. Restarting a second time returns everything to normal. I have not seen the Service Transmission warning again but the check engine light remains on and I got an email from our Jeep Overlords stating I had the Service Transmission error and that I should take it to the dealer.

 

[Earl 392]

2021 stock 392. Just over 15,000 miles. I was gently mudding Sunday evening , the mud was just over the bumper. While moving forward and back in 4wLo with everything locked I got the Service Transmission message on the dash. After extracting myself from the hole, I pulled to the side, took some photos and then left. Upon leaving I soon realized the transmission was not upshifting. I stopped, shutdown and restarted and everything seemed fine. After the ride I hit the car wash and upon leaving I was unable to shift into Reverse. The lever in reverse but the R light would just blink and the Jeep would not move. I put it in Drive and had the same issue with it not shifting. Shut down, restart and went home fine... Next day after a couple attempts to drive I now see a pattern where when the jeep is started, Reverse will not work and Drive will not upshift. Restarting a second time returns everything to normal. I have not seen the Service Transmission warning again but the check engine light remains on and I got an email from our Jeep Overlords stating I had the Service Transmission error and that I should take it to the dealer.

Ah the dealer.... My one and only visit was for my performance exhaust valve not working. The service "advisor" attempted to make me pay for the repair because the technician said it looked like there was a lot of mud on it. I was silent and gave him my best "are you stupid" look until he broke and said "well I know its a jeep, I mean, I get it, we can cover the repair".

Ok, thanks for reading this far. My questions...
1. Anyone seen transmission issues like this?
2. Any troubleshooting suggestions? (I do not like the dealership people and my jeep was not that muddy when it went in last time. You can bet your ass I cleaned it beyond clean today, lol)


Of course this happens 2 days before a lift kit and 37s so I definitely want this resolved under warranty before I get those upgrades.

Thanks in advance. I will update after dealer visit if it goes there.

Mud on it that’s unbelievable that they would even think of saying that. Boo on Jeep

 

[Mr.PoodlePants]

Mud on it that’s unbelievable that they would even think of saying that. Boo on Jeep

If you think that’s bad, I bought a new Escalade and one of the front quarter panels didn’t line up well. I took photos and contacted the dealership. They initially tried to blame it on temperature changes in Michigan causing expansion. I about lost my shit then and there. After I calmed down I told the service advisor that I would walk the lot with him and if we saw a majority of the vehicles exhibited the same issues because they were all out in “Michigan weather” I would reconsider his assessment. By then, he didn’t want to do that but I insisted he walk the lot with me. Of course none were jacked up like mine. So they ended up scheduling me into the body shop. Before the appointment I installed clear side marker lights. (5 min, pull the fender liner back, snap in new lights.). After it was repaired, when i went to pick it up they started making a big deal about how they “discovered” the fender was misaligned because I had installed those marker lights AND that I should be grateful they covered the repairs because Cadillac warranty would not do it. (Mind you, brand new, had it maybe 8weeks at point AND I had photos of the alignment issue from day 2 of ownership and they had looked at it before the marker lights went on.)

I ended up talking to their warranty specialist and the dealership manager about warranty law, how the lights get installed, the whole “Michigan weather” thing and blah blah blah. I’ll never buy another Cadillac.

 

[BL Beast]

Sad to see that most dealerships today approach warranty as, look for a reason not to fix it. I think that's because they are on the ropes and the money is not there. Until something changes, a lot of NEW vehicles are going to sit there. We see it across the board as more and more dealers are in trouble.

 

[Ted392]

Check electrical connections and grounds. Sounds like something is loose. How old is the battery?

 

[Mr.PoodlePants]

Check electrical connections and grounds. Sounds like something is loose. How old is the battery?

Battery is OEM so Late 2021. I dropped it at the dealership this morning. All my vehicles sit on battery tenders if parked for more than a couple days.

 

[RubiconHemi]

Hopefully the dealer won't give you any grief this time. I was thinking maybe there was mud stuck up in the linkage cluster, right near where the front drive shaft connects to the TC. Good luck.. I hate dealerships also...

 

[Mr.PoodlePants]

Good news? Dealership saw errors regarding a transmission pressure sensor on their “scan”. It must be a very extensive scan as it took the 6.5 hours to get that info back to me. The rest of the good news is that they should be able to get the part in 3-8 days. The icing on the cake is no loaner and they want to keep the Jeep because it could apparently end up in neutral until the part is replaced.

Bad news is no lift or new tires this week. Let’s home this pressure sensor resolves the problem.

Cheers!

 

[Mr.PoodlePants]

Problem returned. Service Trasnmission warning in the dash, check engine light and have to start the jeep twice for the transmission to operate correctly. (On the first start it will not shift into reverse or upshift out of first gear). Returned it to the dealership. They had it two day and just informed me that Chrysler wants them to replace the transmission. They are attempting to source the transmission and will update me on timeline when they can. If anyone else has seen this or knows about another instance, I word love to hear about it.

Cheers.

 

[Earl 392]

Problem returned. Service Trasnmission warning in the dash, check engine light and have to start the jeep twice for the transmission to operate correctly. (On the first start it will not shift into reverse or upshift out of first gear). Returned it to the dealership. They had it two day and just informed me that Chrysler wants them to replace the transmission. They are attempting to source the transmission and will update me on timeline when they can. If anyone else has seen this or knows about another instance, I word love to hear about it.

Cheers.

Bummer

 

[Mr.PoodlePants]

Jeep dealership contacted Chrysler and they advised replacing the transmission. Waiting to hear time line estimates on procuring and installing a new tranny. yay...

 

[Earl 392]

Jeep dealership contacted Chrysler and they advised replacing the transmission. Waiting to hear time line estimates on procuring and installing a new tranny. yay...

moving forward I guess

 

[Riad]

I've had the same thing happen to me a couple of days ago. No service transmission light though, just the check engine light.
I've dropped it off to the dealer to check, let's see what they come back with. However, I just had the Jeep regeared to 4:56 a couple of days before all this happened. I noticed some pretty substantial vibrations when I hit about 65mph.
Just wanted to get thoughts from you guys here - could the regearing have caused this? The guy at the shop i got it done from obviously said no however I wasn't completely convinced with the way they worked (even though they came highly recommended). Took them 3 days to do the regearing during which I went in for a test drive after they said they were done and the Jeep made some awful noises ( they told me later their supplier had given them 4.88 for the front ring and pinion by mistake). They blamed the vibration on the front driveshaft (Tom Woods 1350 which never had significant vibration before the regearing). Took it back to the shop who installed the drive shaft and they said there's nothing wrong with the drive shaft. The CEL popped up just as I was dropping the car off to the driveshaft shop so they scanned for codes and told me to go to the dealer.

 

[Robr651]

I've had the same thing happen to me a couple of days ago. No service transmission light though, just the check engine light.
I've dropped it off to the dealer to check, let's see what they come back with. However, I just had the Jeep regeared to 4:56 a couple of days before all this happened. I noticed some pretty substantial vibrations when I hit about 65mph.
Just wanted to get thoughts from you guys here - could the regearing have caused this? The guy at the shop i got it done from obviously said no however I wasn't completely convinced with the way they worked (even though they came highly recommended). Took them 3 days to do the regearing during which I went in for a test drive after they said they were done and the Jeep made some awful noises ( they told me later their supplier had given them 4.88 for the front ring and pinion by mistake). They blamed the vibration on the front driveshaft (Tom Woods 1350 which never had significant vibration before the regearing). Took it back to the shop who installed the drive shaft and they said there's nothing wrong with the drive shaft. The CEL popped up just as I was dropping the car off to the driveshaft shop so they scanned for codes and told me to go to the dealer.

If you didn’t have the issue before the regear I think it’s pretty easy to conclude that’s likely your problem. How did the shop not even know what ratio they were installing? Did you / they adjust the parameters with a programmer after the regear? I think some of your DTC’s can be attributed to that.

 

[Riad]

If you didn’t have the issue before the regear I think it’s pretty easy to conclude that’s likely your problem. How did the shop not even know what ratio they were installing? Did you / they adjust the parameters with a programmer after the regear? I think some of your DTC’s can be attributed to that.

Yeah that's what I figured... shouldve pulled the plug on them after that first test drive and gone to my other shop. Oh well. They told me to get a Tazer to adjust the settings so I ordered one but haven't got it yet.

 

[EBYCREEK]

Just remember that when you changed the gear ration that increased the driveshaft speed going down the road. The faster the driveshaft turns, the more noticeable these driveshaft angle or balance problems become.

 

[CabinDweller392]

Just last week… I pulled out of the driveway and got a service transmission warning. The transmission would not shift out of first gear. I pulled over, shut the Jeep off, started it back up and haven’t had the problem since. I was/am hoping it was just a software glitch that needed a “reboot”. My Jeep is completely stock with only 2,000 miles on it.