42RLE Shift Solenoid Recurring Failures/P0846 Questions

[fastfreddy56]

Hello, A year ago without warning, my 2008 Liberty transmission went to 2nd gear and would not shift properly until I shut off the key and restarted. It seemed fine for a couple weeks then suddenly got worse so I parked it. IT showed a P0846 code for transmission fluid pressure sensor or switch 'B' circuit range performance. Online research seemed to consistently tell me that the Shift Solenoid Pack was failing and needed replaced. At the time I was going through a really busy period and I didn't feel like crawling under it to do the R&R, so for the first time in my life I took my vehicle to a dealership.

The ****** guy assessed and came to the same conclusion, told me he checked all wiring connections, and that the fluid, pan, and filter were spotless, absolutely no metal or debris and was in otherwise good condition so he replaced the shift pack. The transmission worked great for three weeks then started doing the same thing, same P0846 code so I took it back to the dealer. This time the ****** guy wanted to replace the PCM at nearly $2000 and told me that he wouldn't guarantee that would fix it. I got the service manager involved and insisted that the new part had failed and that I would not agree to the PCM unless they guaranteed it would solve the problem. While we were arguing back and forth for a few weeks I bought a reflashed PCM online and swapped it out, nothing changed the same problem existed. Eventually the service manager agreed to replace the shift pack, and I was back on the road-this time for 6 months and now the same failure has happened again. P0846 again.

So here's my hangup. I have found a few instances online where others have experienced repeated shift pack failures and installing a new one seems to get them back on the road - but the shift pack doesn't seem to have anything to do with the transmission fluid pressure sensor or switch. What am I missing? It just seems unlikely that the shift pack is really the problem, and maybe taking the valve body out and putting it back in jostles something around that hides the problem for a while.

Should I replace the entire valve body and shift pack this time or look for something else?

 

[KJowner]

I'd make very sure the wiring was intact before putting the effort and money into a solenoid pack.

 

[fastfreddy56]

That makes sense, thanks for your input. Obviously the connectors and general harness condition, and would you suggest pulling the wiring from the loom to see every inch of each wire too? I saw a youtube video where a guy did that (and didn't find anything wrong).

 

[KJowner]

I'd check continuity end to end after looking closely at the connections.
Also search on here, there will have been other people with similar issues over the years.

 

[fastfreddy56]

I'd check continuity end to end after looking closely at the connections.
Also search on here, there will have been other people with similar issues over the years.

Thanks again. Sounds like a good plan.

 

[budget76]

I agree with these guys. Sounds electrical like some wire grounding or not working after a hard stop and such. Doubt mechanical at this time. FYI fluid drain and fill every 30K for me. (2011)