I found a cool suspension lift kit a pop up camper or trailer that has a Dexter Axle under it. You'll have to climb under and take a look at your axle to find out the make, size, and capacity. From what I've read you have to look on the back side of the axle somewhere in the middle to find out the make.
This kit is again for the Dexter Axle found on many Coleman/Fleetwood and other campers:
Best part... it's $50!!!!!
It's called the Dexter Axle Over/Under Conversion kit