Flexible Sub-Assemblies Not Moving

Hi all, quick question. For a school project, part of what I am doing is having a vehicle run on a track. However, when I add the vehicle assembly to the track assembly, the wheels and gears will not turn; however, they do turn in the vehicle assembly. I have ensured that the sub-assembly is set to flexible, but this still does not fix the problem. Is there something else I can try? Youtube, Google, and my textbook have not been much help. Just to clarify, I'm not asking for someone to do my project for me; rather, I just need some help solving an issue I am having with the software. Thank you.

Edit: Some more information, if it is helpful. In the vehicle sub-assembly, when the chassis is fixed, the axles, wheels, and gears all move. However, when the chassis floats, nothing moves.

Message was edited by: Thomas S

SolidworksAssemblies