Landing gear is BINDING
With single motor it has to drive master leg plus cross bar to slave leg
Reduction gear box, cross bar, drive screws in each leg etc.
Shear pins usually break so I would be looking into drive screw assemblies on each leg for binding
Hitch up to truck and run legs up so trailer is supported by truck
Disconnect cross bar to slave leg and then operate master leg and check how well it runs
Then operate slave leg by turning cross bar by hand-----it should move easily if not binding
That model number is for a Stromberg Carlson Landing Gear.
https://www.etrailer.com/s.aspx?qry=Stromberg+Carlson+landing+gear