[jsb5717]

Curious what you mean by "bucking". I've had zero issues with mine and love how it pulls. The pics in the linked thread are interesting though. Since there aren't other reports of similar damage I have to wonder what's going on there.

The box was mounted rear of the pin...I mount mine the opposite. What size of 5er? If the brakes aren't set correctly the more of the braking would be in the truck causing the trailer to push harder than it should into the pin which could cause that kind of damage over time. Especially with faster stops.

Just speculating