Mine will only upshift on its own when its in sport mode and I don't hit the paddles.
Once I play with the paddles it only down shifts on its own.
I accidently hit the paddles once going around the water box at the dragstrip and I hit the rev limiter just before the 1/8th mile and she threw out the boat anchor costing me an stock 12.9X pass.
Had to settle on the 13.08 as she just didn't want to run that quick again
