Ashleigh xr6t 03

Hey guys I'm new to this thing so bare with me , I have recently brought a xr6t 03 ba auto, no mods. Just the other day I was driving along next minute the car goes (bang) and just rolled on, wouldn't select gears nothing won't select 1, 2, 3, 4 in the sports shift either... any ideas?? No leaking fluids, slight burning smell... HELP :/