A vent system for an axle of a heavy-duty vehicle includes a check valve and an exhaust tube that is connected to the check valve. The check valve includes a first end that is mounted on the axle, a second end, and a body that is disposed between the first and second ends and is in selective fluid communication with the axle interior. The exhaust tube includes a first end that is mounted on the second end of the check valve, and a second end that is open to atmosphere and is in fluid communication with the check valve body. Using any one of a number of types of configurations for the valve body, the vent system selectively exhausts air from the axle interior to atmosphere to relieve buildups of pressure in the axle, while protecting the integrity of the check valve and preventing contaminants from entering the axle.