Ford Car Pack Powertrain Fixes

This mod fixes a vanilla problem affecting the Ford vehicles included with the Road Trip pack, where applying the engine brake caused cars to downshift. You will also no longer be able to manipulate the engine brake using the decrease/increase keybinds. However, the engine brake indicator will still appear in the indicator widget when you press the engine brake keybind. This mod is compatible with sound mods that overwrite the existing "sound.sui" file.