Chevrolet Low Cab Forward 6.7L 2022 Owner's Manual page 251

250 Vehicle Care
plugged to prevent gear oil from leaking
out and dirt or foreign objects from
entering the axle.
If no brake air pressure is available,
manually release the spring brake
chambers. This will allow the wheels to
rotate.
Use a vehicle of equal or greater weight
to pull the vehicle.
Use a tow bar between the towing
vehicle and the disabled vehicle.
If the Parking Brake Cannot be Released
Warning
Do not manually release the rear spring
brake chambers if the vehicle is parked
on a slope. Releasing the rear spring
chambers would disengage the parking
brake and allow the vehicle to roll away,
which could result in serious personal
injury, death and/or property damage.
Releasing a Spring Brake Chamber
1. Firmly chock the wheels.
2. Remove the cap and insert the release
bolt (a tool normally stored attached to
the brake chamber) as far as it goes.
Rotate it 90° clockwise and lock.
3. Pull on the release bolt to make sure
that it is secure, attach the washer and
nut, and tighten them to 3.87 in
(98.4 mm).
4. To remove the release bolt, perform the
same sequence of operations in reverse.
Close the cap securely.