My 5th wheel pin box frames have failed on both my units and that was with regular use without a GN. That failure is to be expected on most unit with a GN.
I see some being used and it makes me feel scared even used by others. One occasion with trailer brake failure and the pin box frame will end up failing.
Barbara and Laurent, Hartland Big Country 3500RL. 39 ft long and 15500 GVW.
2005 Ford F250 SD, XL F250 4x4, Long Box, 6.0L Diesel, 6 Speed Stick, Hypertech Max Energy for Fuel mileage of 21 MPusG empty, 12.6 MPusG pulling the BC. ScangaugeII for display..