Coupling Devices (Fifth Wheel)

In many cases, drivers have mistakenly thought that their fifth wheel was locked onto their trailer, only to find that it was not locked in. Keep in mind that when you tug test the hook into the trailer, the weight of the cargo in the trailer can cause you to believe that you are locked in because the weight is holding the trailer back. When hooking into a trailer, the first thing you should do is physically verify that the locking jaw is secure around the kingpin, then a tug test should be done, forwards and backwards.