Glad this came up and helpful info!
While jeeping around Moab this last week I had a few occurrences where the rear locker would not hold the lock (driver rear wheel) during some of the more vertical climbs on MM & SB and sometimes it would happen halfway up. It was not all the time and was not like the compressor was coming on due to leaking.
I found if I quickly dumped the back locker and replenished using their arb SK12, it would keep it locked thru the climb. It seemed more like I just needed more air and this thread seems to supports my suspension. I verified my SK12 has the original 70-100 psi and ordered a 90-120 switch which would not make it to me before leaving Moab but it would be a lot less costly then tearing the locker apart. The switches only cost a few bucks so I think now I'll also get one that goes to 150 as a second test.
Maybe the jeep gods will shine on me and I'll fix my issue for less than $20.00.
Thanks