Parking Brakes, Hills, Water, and Adverse Conditions
Parking securely
Come to a full stop, apply the parking brake (yellow diamond knob), then release the service brake. On any grade, chock the wheels - spring brakes are strong, but the standard is chocks plus parking brake. Parked on a hill with a curb, turn the front wheels into the curb facing downhill and away from the curb facing uphill; with no curb, turn the wheels toward the edge of the road.
Hills
Downshift before the grade, not on it. Check the brakes with a firm low-speed stop at the top. Descend at a speed that still lets you stop, and use snubbing rather than continuous pressure.
Water
After driving through deep water the brakes are wet, and one side may grab harder than the other. Drive slowly and apply the brakes gently a few times to heat and dry them, then test at low speed before returning to highway speed. If the truck still pulls, stop and dry them further.
Ice, snow, and rain
Reduce speed, increase following distance, and brake earlier and more gently. ABS helps you steer but does not shorten stopping distance on ice. Avoid engine braking on very slippery surfaces - the drive wheels can break traction.
Traps: the trailer hand valve is not a parking brake, and draining the tanks is a daily moisture-removal job, not a parking step. If air leaks off while the truck sits parked, the spring brakes stay applied - that is normal, not a fault.
Rule of thumb: parking brake, then chocks, then let off the pedal - and turn the wheels so gravity rolls you away from traffic, not into it.