Trans code w/o any symptoms?

nondem

TJ Enthusiast
Original poster
Joined
Apr 17, 2021
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197
Location
Tallahassee, Fl. USA
This transmission previously has had several episodes where solenoid starts acting up and won't shift into 3rd gear...ends up in limp mode.
It took a while of living with it to figure out it only happens when the trans is at the upper end of the temp range...like going through some thick sand on a really hot Florida day.
It self corrects if I let it cool a bit(and unhook the battery to reset it).
So, knowing these 42RLE transmissions need more cooling and NOT knowing how much life is left in this transmission as a whole w/o a CVI reading...I installed a stacked plate trans cooler to see how things went.
Since installing the cooler I've not had the solenoid issue happen a single time. When not having the solenoid issue the transmission has always operated perfectly and has no other issues that I can tell.
Per the carfax(fwiw) it was rebuilt by AAMCO about 60k miles ago.

So, yesterday I took the TJ offroading w/a friend that has an LJ. The Jeep and Savvy shifter worked flawlessly btw - I would recommend replacing that wonky shift linkage to anyone.
The day involved about 30 miles of dirt roads w/the odd mudhole. After maybe an hour straight of 10-15 mph max putting along dodging bumps I got a CEL.
Other than the CEL light, the trans worked perfectly and continued to do so for the rest of the day. It happened the instant I turned the A/C off but I'm thinking that was just a coincidence.
I pulled the code and got PO846 which is trans fluid pressure sensor switch B Circuit Range Performance. It looks like that is also related to that solenoid pack.
I've had other solenoid pack related codes when it went into limp mode etc...but never this one.

So, finally my question: I may yet eventually replace that Solenoid pack but I'm in the process of moving so it's not a good time. This isn't my DD.
Since the trans is (apparently) functioning perfectly I'm wondering if I'm risking damage by just running it like it is and clearing the code if/when it pops up again.

As I mentioned, it shifts fine and doesn't seem to be slipping at all but I know slipping isn't always obvious.
 
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Reactions: Jerry Bransford
When was the last time the fluid and filter were changed? Given that code, and other issues you've described, at a minimum I'd drop the pan and check it for contaminants. Unfortunately, that would also be the time to install new solenoids, but that's a much more involved job.

In the interim, you could always order a new Dorman pan (with a drain plug), Mopar filter, LubeLocker gasket, and 6 quarts of ATF +4. At least that way going back in later would be much easier and less messy.
 
When was the last time the fluid and filter were changed? Given that code, and other issues you've described, at a minimum I'd drop the pan and check it for contaminants. Unfortunately, that would also be the time to install new solenoids, but that's a much more involved job.

In the interim, you could always order a new Dorman pan (with a drain plug), Mopar filter, LubeLocker gasket, and 6 quarts of ATF +4. At least that way going back in later would be much easier and less messy.

Thanks for the reply.
The fluid still looks brand new/cherry red. I've not dropped the pan yet because I'm skert of what I might find :)
Yea, I think I'll get the pan w/the drain and a lubelocker for it and see what it looks like inside. I need to take it to a shop that can read the Clutch Volume Index which will tell me if it's worth it to do the solenoids.
 
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Reactions: Irun
Just an update...After double-checking the fluid level I attempted to clear the code but it instantly comes back. However, I took the Jeep out for about a 30 mile mixed road/woods drive. This included some spirited hill climbs. The Jeep never missed a beat, shifted and operated perfectly the whole time in all gears including OD.
Other than the CEL there is nothing to complain about. Gonna be tough to convince myself to do the solenoids w/the CEL being the only thing :)