SPECIFICATIONS. Additional information. The 3XGN from Big Tex Trailers is our super heavy-duty gooseneck trailer. This unit comes equipped with 15,000-lb axles and is perfect for hauling even the heaviest equipment. Enjoy peace of mind when standing up to the rugged conditions with the 3XGN. 2-5/16″ Ball Adjustable Coupler- Square Crank Type.