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Difficulty: MediumBrake Failure

When experiencing total service brake failure while descending a downgrade, shifting the transmission into neutral allows the driver to safely match engine RPM before engaging a lower gear.

Answer: Answer

Answer

False
The statement is false because shifting into neutral eliminates all engine retarding forces and causes the vehicle to accelerate out of control. Once in neutral on a downgrade, the transmission cannot be forced into a lower gear due to rotational speed mismatches.

Step-by-Step Solution

1
Evaluate the effect of shifting into neutral during a downgrade emergency.
Putting the transmission in neutral completely disengages the engine from the drivetrain, eliminating engine braking.
Engine compression retarding power is the primary tool available to manage speed when service brakes have failed.
2
Analyze transmission behavior when attempting to shift back into gear at high downhill speeds.
The runaway vehicle accelerates rapidly, creating an unbridgeable RPM difference that locks the transmission out of all gears.
Commercial vehicle transmissions cannot synchronize when vehicle road speed far exceeds engine governing capabilities.
3
Determine the truth value of the statement.
The statement is false.
Drivers must never coast or shift into neutral during a descent or brake failure.

Key Concept

Engine Braking and Transmission Control During Downgrade Brake Failure
Estimated Time:1m 0s
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Topics

Brake Failure

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