I have a 2011 Shelby GT500 that has the 1st to 2nd grind at higher rpm's shift. I have seen some older forums where shifters, oil brands, and repairs from the dealer has helped. I have taken my car to the dealer today, and they said there's not any TSB's on the issue. They said I may have to pay 100.00 for diagnostic if they find it not to be internal in the trans. This car has 25k miles and is bone stock. I have seen the video where Ford says the have corrected the issue in the 2013's. Any advise on this??