My Ford expeditions transmission is causing unsafe driving with rough sound and thunking noise. There is a C,D,F issue and valve separator parts that are the initial issue that can cause major issues for me and many others. A Ford technician advised me that TSBs exist and made me aware that my cost could be $199 (diagnostics), $1500 (parts), and $4400 or more (transmission repair or replacement). Why is this danger still be allowed with a well known issue. The problem started and appears to be getting worse. Why is Ford being held accountable for this lack of quality in their vehicles.