I have a 1998 enclosed car hauler I got from my work, my DMV paperwork states it as a 7,000lbs trailer, everyone I work with is telling me its a 10,000lbs custom built trailer. We can't find any build paperwork or who made the trailer because they have moved to another state. How can I tell if it is a 7,000lbs or 10,000lbs trailer.
<- the trailer. Its 21' , and the trailer empty weight is 1920lbs. I need to haul 2 tool boxes that weigh 3,000lbs ea a total of 400 miles. I dont want to be overloaded

Normally the 3500lb axles are 5 lug, and the 5000lb axles are 6 lug, IIRC. Look at the tires weight rating too.

That is what I was going to say as well.

If there leaf spring axles, a 3500 lb. axle will be 2 3/8" diameter beam. 5200 lb axles. will be 3" beam. 5 bolt will be 3500, but 6 bolt can be either axle.

I just spoke to a trailer co willing to listen to my question. He said don't go by how many lugs hold the wheel on. He said some 5000lb axles were made to fit 5 lug drumbs if the trailer had limited wheel well room. He said look at the mounting plate where the brake assembly bolts to the axle, If it has 4 bolts it's a 3500lb axle, 5 bolt 5000lb axle. Thanks for the help everyone!!!

Crawl under the trailer, look around the beams. Find any numbers you can and write them down. Shoot me a PM and I can get you the information. W/O those numbers you are shooting in the dark.