I may be a little late to the party, but I'll add my comments.
If there is a chance you can post pictures of your front, rear axle and center axle hangers, we can see if you have the "issue".
So what is the "issue"?
Back in the early year 2,000's, campers started getting more I beam style frames across the industry. As time went on, cracks started forming in the web of the I beam just above the hangers from the hangers flexing in turns. The longer the hangers, the worse this was. The more miles towed, the worse it was.
Soon a pattern to the cracks was evident. There was lack of rigid support between lower flange of the I beam and the web. The lower flange would flex and over time crack the web.
These I shape manufactured housing beams used for campers have very weak lower flanges. Some RV manufacturers addressed the problem by adding support to the lower flange. This halted the web flexing and then no more cracks.
This made it to be a big enough problem that there is even a Lippert how to fix it sheet on the NTHSA website. Yet, we still have campers being built today with the same issue. No lower flange support on long hanger suspension.
I learned about this in the later 2,000's and I made my own cross member supports to go between all 3 hanger sets. Guys who go off road, like toy haulers knew of the issue as their off road travel to camp aggravated the problem worse then the asphalt road folks. The toy haulers guys where welding in channel iron stiffeners on brand new campers to ward off the issue.
Picking up from the toy hauler group, I reinforced the hanger itself and the frame. My camper, while a travel trailer in place of a 5'er, has the heavier 10" I shape frame with 5" long hangers and loaded weighs just under 10,000# scaled. My issue was hanger bending when turning and staying bent. I never cracked the frame as the reinforcing tubes and the added flange support stopped it.
I even have a picture filled post here on RV.net on this, but for some reason all the pictures are not viewing on that older thread.
Bottom line: If you plan to keep your camper a good while, adding hanger reinforcement at all 3 locations is a worthwhile upgrade.
Since I cannot see yours, I do not know what you have.
Hope this helps
John
PS. Here a couple of the pics linked in. If you are interested in more, let me know
2005 Ford F350 Super Duty, 4x4; 6.8L V10 with 4.10 RA, 21,000 GCWR, 11,000 GVWR, upgraded 2 1/2" Towbeast Receiver. Hitched with a 1,700# Reese HP WD, HP Dual Cam to a 2004 Sunline Solaris T310R travel trailer.