I have a Car with six wheels all which collide and the wheel colliers are separate objects from the wheel. without a rigid body attached to the axles/suspension the axles and wheels stay attached to the car, but when i add a rigid body to all the axles so my antirollbar code works, the axles all suddenly fall off the car. The wheels stay attached to the axles but the axles all fall off.
I think you might need to make the axles a child object to the car body. if you’ve done that already, I don’t know.