Allison Man I have a 2002 GMC DuraMax/Allison it has just started to shift very rough especially when shifting into reverse,it slams in pretty hard.I also noticed that the indicator lights that tell you which gear you are in only work intermittently.Once you are underway and driving down the road the transmission works fine and seems to shift and downshift with no problems.Hope you can help as I need this truck and can t get it in the shop for almost a week as they are booked.