CDL Combination Test Questions (Page 1)

When checking that the trailer is securely coupled to the tractor, the landing gear should be:

• Fully raised.

• Fully lowered.

• Slightly raised.

When coupling, the proper position of the fifth wheel is:

• Tilted towards the end of the tractor.

• Level with the ground.

• Tilted down towards the end of the tractor.

When you are uncoupling a loaded trailer, you should lower the landing gear until it:

• Makes firm contact with the ground and lifts the trailer off the fifth wheel.

• Just touches the ground.

• Makes firm contact with the ground, then crank it in low gear a few extra turns.

Having antilock brakes on only your trailer:

• Will increase the likelihood of jackknifing when braking.

• Will increase the likelihood of a rear wheel power unit skid when braking.

• Will give you more control over the vehicle when braking.

The air leakage rate for a combination vehicle (engine off, brakes on) should be no more than ___ psi in one minute.

• 2

• 4

• 3