CDL Driving Safely: Shifting Gears

Manual Transmission

  • If a vehicle has a synchronized manual transmission, you do not need to double clutch.
  • To shift up:
    • Release accelerator, push in clutch and shift to neutral at once.
    • Release clutch.
    • Let hears and engine slow down to the rpm needed for next gear.
    • Push in clutch and shift to higher gear at once.
    • Release clutch and press accelerator at same time.
  • If you have trouble putting into next gear:
    • Stay calm.
    • Return to neutral, release clutch, increase engine speed and try again.
  • When do you shift up?
    • Use engine speed (rpm): when engine hits the top of the range for that gear.
    • Use road speed (mph): learn what gears are good for what road speed.
  • To shift down:
    • Release accelerator, push in clutch and shift to neutral at once.
    • Release clutch.
    • Let hears and engine slow down to the rpm needed for next gear.
    • Push in clutch and shift to lower gear at once.
    • Release clutch and press accelerator at same time.
  • Special conditions to downshift:
    • Before starting down a hill.
    • Before entering a curve.

Multi-Speed Rear Axles and Auxiliary Transmissions

  • Used to provide extra gears.
  • Control them by a selector knob or switch on the gearshift lever.

Automatic Transmission

  • Select a low grade to get greater engine braking on low grades or poor road conditions.

Retarders

  • Help slow a vehicle, reducing the need for brakes.
  • Reduce brake wear and give another way to slow down.
  • Can be turned off or on by the driver.
  • Can be noisy, so may be prohibited, especially in populated areas
  • If roads have poor traction, retarders can cause you to skid.