I recently did a 2-5" Journeys (2in) lift on my 2005 GMC Safari, everything looked good but when I started driving the car would struggle to get going for a few seconds, then I would hear a transmission switching sound, and the service AWD light would come on and the van would start moving. It feels like the transfer case is disengaging the back wheels.
It drives fine otherwise and I drove on the highway for an hour with no issues.
Let me know what could be causing this. I bought an engine code reader that should come in later this weekend.