I have a 2007 Avalanche. Last week it would not go in reverse. I was on my way home and the transmission gave out. I pulled over and tried to get it back into geat. The gear shift would move but nothing. The position indicator did not show that it was moving from Park to anu other position. The mechinic just called and said it was driving fine. Back story the car got wet a year ago in NC during the hurricane. It did not stall I just HAD to drive thru high water to evacuate. Ever since then when it rains or the under carrage gets wet it acts up and shifts hard.