Transfer Case problems of the 2008 Jeep Cherokee

I started to get service 4 wd system light this started after I had taken vehicle in for recall about transfer case neutral problem. I had never had a problem before this had it looked at by certified mechanic. He checked all systems and they checked out ok he cleared error code. A day or so later it returned. He said I should return to dealer. They said it was a bad transfer case range sensor. A deeper look and I found that many people have had this same trouble after having flash update for recall. This part has a large back order ( I was told by dealer part over 500 piece ) and they could only order one every 14 days.