General Knowledge: Shifting

7 questions in the bank cover this topic. Everything below is drawn from the sources those questions cite.

Sources: 49 CFR 392.10, TC 21-305-20 para 12-4, TC 21-305-20 para 12-5, TC 21-305-20 para 3-14

What you need to know

392.10(a) requires crossing in a gear that permits completing the crossing without a change of gears, and expressly prohibits shifting gears while crossing the tracks.

You must not shift while crossing the tracks.

When it is safe to do so, the driver may drive the commercial motor vehicle across the tracks in a gear that permits the commercial motor vehicle to complete the crossing without a change of gears. The driver must not shift gears while crossing the tracks.

49 CFR 392.10

Riding the clutch applies slight constant pressure, which the manual says causes excessive wear.

It also means the clutch is never fully engaged, so power delivery to the wheels is not what you think it is.

The vehicle operator’s foot should not be on the clutch pedal except when actually starting, stopping, or shifting gears. Even a slight constant pressure on the clutch pedal causes excessive wear.

TC 21-305-20 para 12-4

Slipping the clutch to hold position burns the friction surface and gives you no margin if it lets go.

The brakes are designed for holding; the clutch is not.

when stopped on a hill, never slip the clutch to keep from rolling backward; instead use the brakes

TC 21-305-20 para 12-4

With the clutch down the engine is disconnected, so you lose engine braking and the ability to accelerate out of trouble.

The manual says to be below 15 mph before pressing the clutch to stop or turn. Both follow from riding the clutch.

When slowing a government vehicle to stop or to turn, be sure to reduce speed to 15 MPH or less before pressing the clutch pedal. Coasting a vehicle at a high speed with the clutch pedal pressed is dangerous.

TC 21-305-20 para 12-5

Neutral with the clutch released takes the load off the release bearing.

Sitting with the clutch held down for minutes at a time is what wears it out.

While waiting in a long line at traffic lights or when halted for other reasons, press the clutch pedal and move the transmission shift lever into neutral. Release the clutch after shifting into neutral.

TC 21-305-20 para 12-4

Shifting outside the engine's range either over-revs it or drops it below the power it needs, and either way you lose the engine braking you shifted for.

Downshift within the operating range of the engine (revolutions per minute [RPM]) (if manual transmission).

TC 21-305-20 para 3-14

Neutral first, then just enough brake to hold.

Sitting with the clutch down wears the release bearing and leaves you one slip away from moving.

After stopping, shift to neutral and reapply the brake just enough to keep the vehicle stationary.

TC 21-305-20 para 3-14

Check yourself

• What is the rule on gear selection at a railroad crossing?

• When should your foot be on the clutch pedal?

• How do you hold the vehicle when stopped on an upgrade?

• What is the result of riding the clutch?

• How should you handle a long stop in traffic?

• What governs when you downshift during braking?

• What is the gear and brake sequence once you have stopped?

Answers are in the practice test for this topic.