How to uncouple a trailer... for dummies

Ah yes, Great Dane, I love them. One of my past employers bought 25 new trailers from them years ago that had to get the door frames reinforced (twice) because the doors wouldn’t close. Great Dane attempted to fix them once and failed so we had to fix them ourselves (needless to say they lost our business). But that’s a story for another day.

So their manual says that during coupling, the 5th wheel should raise the trailer slightly when you back into it. That means, when you uncouple, the trailer should drop slightly off the 5th wheel when you pull away. Right? That was meant to be the main takeaway of my original post. But in all my years, and in every tractor I’ve driven, and at every company I’ve driven for, it seems like almost every single trailer I have ever coupled was higher than my 5th wheel.

The procedure I described in my original post is how I learned how to do it in CDL school, and that method has worked flawlessly for me ever since.

 

In my experience, what causes the landing gear to bind is when they are on the ground and the trailer tries to move in either direction, either from a truck doing a tug test or from an impatient forklift dummy ramming heavy pallets into the trailer.

If you back under the trailer and let the 5th wheel take the weight off the landing gear, it will unbind.

And i never meant you should “drop” the trailer on the landing gear. That’s why I suggested dumping the air bags to let the trailer settle gently on the landing gear. But other posters have informed me that many tractors don’t even have a dump valve, so idk what to say about that.

 

I’ve spent some time as a yard dog and I can assure you, MOST of them are complete idiots. I yard dogged at a paper company that had a dirt drop lot with a concrete pad for the landing gear. If you were pulling a trailer from the dock (where it is level) to the dirt lot, you would have to raise the legs a bit to compensate for that concrete pad, and vice versa if you were taking a trailer from the dirt lot to the dock. To further complicate the situation, one end of the lot sloped upward a little, so you would have to raise them up even higher if you dropped there to compensate for the pad and the incline.

As I said, most of the drivers were idiots and they just didn’t get it. I would see them drop a trailer and pull away with their fifth wheels still several inches up. Or they would drop a trailer and the trailer would fall several inches and slam down on the landing gear, and they would just drive off like nothing happened. They couldn’t understand why the trailer would be the right height sitting in the dock and too high sitting in the drop lot. Ugh... it was frustrating.