Todd,
I wish I had an answer for your question about the service rep. All I can say is that when mine went nuts, I was close to the dealer and I headed straight there and left the darn car RUNNING so that they could observe all the faults and get as much data as possible...'cause I'd been burned before by faults not leaving a code.
That said, here is the deal:
There is a manufacturing defect in the locking rear differential. There was some machined part out of tolerance and the mechanism will not lock up fully. So the control unit thinks it's locked and the sensors may not....that is about as well as I can explain it. What results is a miscommunication between the control unit and the transmission control unit. The fault is then reported through the tranny as a "transmission fault."
I literally poured over all the fault codes at my service writer's desk and saw what led them to that conclusion myself. I also spoke with a regional service manager and asked him questions ad nauseum about this problem and others (like suspension probs and NAV issues...and climate control/vent issues).
Anyway, they actually were experiencing about a 40% defect rate with the locking diffs. The open diffs are fine. They've "cleansed" their supply line so if your service dept. has a spare or has to order a spare, it should be ok. They will just replace the rear diff as a whole.
I had this done about 2 weeks ago...and so far, no problems.
I have to give Seattle Land Rover a lot of credit for not only fixing this problem, but having the tolerance to deal with me ! I'm a pain in the A$$ ! ...and I'm a Systems Engineer so I think I know it all anyhow. ...but really, to get my car into their shop and me into a Jag for 4 days without even an appointment....that's pretty good service. ...and I LITERALLY left the car running as I left the premises!
Like I told dude on the phone (the manager from LRNA), I know this car is going to have issues, being a 1st year model...I'm willing to work through them as long as there is a commitment to take care of us beta-testers !!
Anyway, Todd.....good luck. I'm pretty sure that is the fix. Your service dept. should either know about it or be able to call LRNA and find out about it.