The other day I decided to change my tune. I was running gearhead's SRL and switched over to gearhead's max fuel tune. The truck runs fine when in drive. Good acceleration, shifts hard and smooth, everything you would expect. However, when i go into reverse something weird happens. If I just idle out it will feel normal but if I accelerate it feels like the gears are not fully engaged and are slipping really bad. It makes a buzz sound and you can feel the vibration coming from under the truck. If you have ever had a four wheeler and tried to shift it into gear while the rpm is too high and hear that buzz it sounds like that. I returned it to stock and switched it back to the SRL and it is still doing it. Anyone else had this happen? Truck has 55k miles on it.