USE OF CHOCK BLOCKS WHEN UNCOUPLING)
UNCOUPLING FROM THE SEMITRAILER
a. Shift range selector to Neutral (N) and apply parking brake. Verify that parking
brake indicator lamp comes on. This will keep your tractor from running out from
under the semitrailer when you unlock the fifth wheel.
b. Pull out the trailer air supply valve.
c. Leave cab and block trailer wheels with chocks as previously explained.
d. Lower the semitrailer landing gear until the bases or wheels touch the ground.
Then, turn the crank two more revolutions so that when the trailer is uncoupled,
it will not drop down sharply and will be nearly level.
e. Disconnect and secure the trailer air hoses and lamp cable(s).