Troubleshooting Excessive Bucking While Towing a 5th Wheel Trailer

Updated 05/22/2018 | Published 05/21/2018

Question:

I have a 2011 3500 Silverado with a BandW turnover ball and companion 5th wheel hitch. I recently was towing a 40ft 5th wheel back from the desert and noticed violent back forth jarring. I am use to a little bit of “chucking” but this was more intense. It seemed most prominent at 55mph and while under load. The symptoms lessened when I took my foot off the loud pedal. Additionally there was two times during mild to moderate brake application that front end was being jarred so bad I almost couldn’t stop. I checked my kingpin location and it was almost dead on centerline maybe even a half inch in front of it. The trailer sat almost perfectly level. Initially I was wondering if their was something wrong with the trailer brakes so I played with the gain. Initially I had the gain set around 8 via my factory brake controller. While towing the trailer it felt heavier then usual with it at this setting so I lowered the gain to .5. The trailer felt way lighter and the jarring affect was significantly less. Additionally one of the times it acted up under braking I lowered the gain and that lessened the affect as well. I am wondering where the potential issue is and / or is there possibly more then one issue going on. If you need anymore info about the set up or the symptoms felt please feel free to contact me.

asked by: Robert

Expert Reply:

My first thought is that something is going on with the wiring on either the truck's brake output circuit or on the trailer's brake wiring. I would start by inspecting and cleaning both the trailer and truck's 7-way connectors. Then use a circuit tester, like # PTW2993, and test the truck's at the 5 O'clock pin while someone engages the manual override. With a factory integrated controller, I doubt this is your issue, but this'll rule it out right away.

I'm thinking the issue is on the trailer. Are the brakes on the trailer new? They may be adjusted too much and need to be backed off. Or are they staying activated when braking? Inspect the wiring from the brake assemblies for any damage or exposed wiring.

If none of this helps you get to the root of the problem, let me know and we'll keep troubleshooting.

expert reply by: Charles S