Check your texture materials uv and more than one texture is ready
Check your animation set for your vehicle correct name and not misspell name.
Check your mesh that is triangle. Three point vertex only.
Check your bone rotation and position that is in the right spot. The head will use as point.
check your mesh damages parts. Keep the bones and the mesh within the same area.
Export Time
When you are exporting your files there will be console output display when your finish your export. There a simple information about it and it will tell basic information.
