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Uncoupling Steps & Safety

After unlocking the fifth wheel, how should you pull away from the trailer?

  • A.Accelerate quickly to get fully clear in one move
  • B.Back up first, then pull out
  • C.Pull forward slowly, stop when the fifth wheel is clear of the kingpin but still under the trailer, and check that the trailer is stable
  • D.Pull out at an angle to test the gear
Correct answer

C. Pull forward slowly, stop when the fifth wheel is clear of the kingpin but still under the trailer, and check that the trailer is stable

Why

The pause while still partly under the trailer is your safety net: if the gear fails, the tractor can still catch the trailer. Only after you see the trailer standing stable do you pull completely clear.

Manual topic: Combination Vehicles - Uncoupling · From the Combination Vehicles practice bank (CV-044).

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