I recently reviewed the codes after having trouble with ISTA reading in German and the NT510 not showing at what mileage the codes occurred and then a nasty breakup sidelined things for a few months. The codes that I pulled did not show anything until the point that I disconnected the transfer case. So, that really didn't give me anything to go on.

I might just replace the wheel speed sensor on both of the front wheels. Other things I have done is replace the front driveshaft (unrelated), replace the transfer case motor gear, replace the transfer case fluid, differential fluids, and transmission fluid. I haven't started the car yet, as I'm waiting for my DDE to return from tuning, and then I will reconnect the transfer case module, and can start fresh with potential codes. Of course I'll be holding on to the steering wheel tightly to avoid getting pulled into a ditch.

Sorry that doesn't really help m5james, but it seems like your symptoms might be different anyway. What do your codes say?