If you're unable to find a model number on your current landing gears then you only have two options; contact the manufacturer of the trailer to see if they have the part number or replace the entire landing gear set. If you're going to replace the landing gears then you'll want to measure the weld stops to find a match so that you don't have to cut off the hangers and weld on new ones.
I've attached a diagram of the Ultra-Fab Deluxe Electric Landing Gear Set # UF17-943010 to give you... view full answer...