My father-in-law is traveling the country in his RV and flat towing his Grande. So he is flat towing with the t-case in neutral, then when he unhooks it and goes to put it in 2 wheel drive it gets stuck in 4 hi. The shifter goes to the 2wd position but the Jeep is in 4 hi. Now this is the 2nd time this happened, first time he brought it to a dealership and they serviced the t-case. Now it has happened again. He has tried backing up and going foward, still no luck. Something internal wouldn't you say. Any ideas.