HISTORY: When I purchased my 2005 (Build Date Oct 1 2004) Montana Big Sky RV in Dec 2007, it had about 5000 miles on it per the seller. At that time I installed the Star Performance Kingpin Adapter. In June of 2012 I encountered the worst washboard concrete in New Orleans just as you get off the new, smooth I-10 Bridge across Lake Pontchartrain. The porpoising motion was so bad I had to slow to 40 MPH. On our next campout (16,626 towed miles) I noticed the back of the horizontal Pinbox plate the Kingpin is attached to was slightly bent up. RV Service Center agreed it was not a big deal. However in June of 2014 I once again encountered nasty washboard cement on I-57 in IL and noticed the Kingpin plate was bent just a little more (27,542 towed miles) so I was convinced by Lippert/Reese marketing to try their new Double Shock with Airbag Goosebox approved for use on Lippert Frames as I was afraid the Kingpin plate might just keep bending and fail. As it turned out I only towed my RV for 9 more months and about 5000 miles before the frame broke and ended up twisting and preventing operation of the Goosebox.
With a track record like that its amazing its lasted as long as it did. As others have said we have frame cracks in that area with a regular 5th wheel hitch.... myself included.
