Shifting Gears
Shifting-gear questions test whether you can keep a heavy vehicle in the right gear, especially on grades, without damaging the drivetrain or losing braking control.
The clutch and the pattern
In a non-synchronized manual transmission, double-clutch: push the clutch, shift to neutral, release the clutch, match engine speed, push the clutch again, and engage the next gear. Upshift progressively - use the lowest rpm that pulls the load - to save fuel and reduce wear. Never ride the clutch or hold the vehicle on a hill with it. Do not coast in neutral; you lose engine braking and the ability to accelerate out of trouble.
Grades and engine speed
Before a downgrade, slow down and downshift. Choose a gear that holds your speed without service brakes; if rpm climbs toward the governed limit, you waited too long. Use engine braking and a steady, firm brake application rather than light continuous pressure, which overheats drums. If brakes fade, downshift and find an escape route.
Worked example
You approach a 6% downgrade at 55 mph with 40,000 pounds aboard. The correct move is to slow to about 35 mph and select a gear that holds 35 mph at 1,800 rpm, before the grade. If you enter at 55 mph in high gear, you must brake hard and downshift while the vehicle is already accelerating - the classic recipe for a runaway.
Traps
Shifting into neutral at a stoplight; skipping the neutral clutch release; upshifting early and lugging the engine; and watching the tachometer while ignoring the speed on the grade.