If it's a 2D layer, just set the rotate property, that's the easiest. If it's a 3D layer, and it's a side view, I think just change the Z rotation property (I haven't tested this with illustrator files though). Also, ensure the anchor point is in the middle of the wheel(s) on their layers..
EDIT: the above assumes the image is of the side view of the truck. If everything is in perspective (and not a flat, side view) it probably won't work using the method I described.
@A.I.1 is correct. If you built this in perspective view then as soon as you do anything with your layers that changes the position or rotation that perspective you created in Illustrator will break. You would have to create everything flat and without perspective in Illustrator and then build a 3D scene in Ae if you want to animate. You can then use a 3D camera to move around the scene and set the perspective you want.
As the others already said, you wasted your time by doing too much in AI. You have to create everything with effects and layers in AE. The tire treads for instance could be mapped to CC Cylinder and animated whereas the sidewalls would quite likely be simple 3D layers rotating about.