I have an '07 F 150 Supercrew with the 4.6 and have had the XCal3 from VMP on for about 8 months and 20,000 miles and have loved it. About a month ago, at 72,000 miles on the truck my transmission went out. Fortunately I had purchased the 100,000 mile warranty and Ford said it was just a failed torque converter seal. They didn't give me a hard time about the tuner but just for my peace of mind, the tuner wouldn't have had anything to do with the torque converter failing would it? I want to keep running the tuner for as long as I own the truck and don't want to worry about it. Have any of you heard of the F150s having transmission problems? The most I've ever towed is my 19' ski boat on a single axle trailer. I do a lot of stop and start and idling for my job in construction though. Thanks.