Too many questions unanswered:
Does it have working brakes on both axles? Does it have good high capacity trailer or light truck tires, or old passenger tires? How far are you going? How fast? What is the trucks tow rating? What is the trailer ball rating? Trailer coupler rating? Etc, etc, etc.
The car hauler trailer probably has two 3500lb capacity axles giving it about a 6000lb capacity. So you will be starting about a ton overweight on the trailer.
Is the benefit worth the risk?