17. Slowly back tractor vehicle until fifth wheel jaws lock around kingpin. Stop tractor vehicle.
Daylight should not show between top of fifth wheel plate and bottom of semitrailer.
18. Assistant visually checks that kingpin is in fifth wheel throat.
19. Ensure primary lock release handle (8) is completely in.
If coupling is not secure, rock tractor vehicle back and forth slowly until kingpin is locked in
20. Inch tractor vehicle forward to check coupling.
21. Set transmission range selector (11) to N (neutral).