Axle Problem 2015 182G

Your problem is pretty common and is usually caused by the inboard mounting of the axle to the rpod frame, which results in the axle being cantilevered.

There should be a sticker on the axle with model and serial number. Most are manufactured by Lippert.

You can upgrade from a 3500 lb to a 4400 lb axle. The brake back plate to back plate dimension, the mounting spacing, and the takeoff angle of the torsion arms need to match what you have.

Note that the heavier axle has 6 lugs so you will need new wheels as well as tires. You can go with 15 inch wheels but you will need an able riser kit if you don't already have one.

Edit: if you have a good trailer shop in your area you could consider getting your current axle straightened and then reinforce it, assuming it's the diamond axle tube that's bent. A simple reinforcement is to ubolt a 2x2 steel angle under the existing axle, using 2 ubolts at each end each at 45 degrees. The angle should be slightly crowned to mate up to the axle which should be also be crowned in the center. I did the reinforcement on mine before it got bent. If you do an advanced search you should find my posting.