Like this?
dropbox.com/s/lhrwer9zr0xudb7/PlatformCar.c3p
Both wheels have platform behavior and connected with pin. It's not a good solution and will only work if the terrain doesn't have big drops, jumps etc. You can make the drive smoother if you don't rotate the wheels. (Make them invisible and pin a different rotating/animated sprite to them)
A better way of doing this is with physics, here is a simple demo:
dropbox.com/s/t9qddhf8q85270j/CarPhysics.c3p