Pontiac Bonneville Transmission HARD SHIFT

My Bonneville Was Shifting Hard After Driving 20 Mi. I Took It To Dealer April 17,21,23,24 Had The Modgulor On Powertrain Replaced Still...

I Just Had A New Engine Installed And Now My Automatic Transmission Is Shifting Hard. I Changed The Fluid And Filter But Did Not Do A...

Our 2000 Pontiac Bonneville Shutters A Lot While Accelerating Into Gears . Sometimes It Dosnt Want To Even Go. What Can Be Wrong With It?...