Need some expert advice. I have a 2011 GT and during the track day yesterday developed some gear box issues. Came off the track aftr the first afternoon session and found I couldn't get the thing into reverse. Tested in the paddock and found that all forward gears are working. Drove home and tried reverse again - no go. Back up lights and rear camera come on but will not engage reverse. Would this be a linkage problem or (hopefully not) an internal problem?