What jwedell uses to figure out towing capacity is a pretty good formula. You should be able to find the dry weight for your trailer on a sticker inside one of the kitchen cabinets. The Gross Vehicle Weight Rating should be on a sticker on the outside of the trailer somewhere near the left front corner of the rig. The GVWR is to TOTAL maximum weight that the trailer can weigh without being overloaded. Your truck's towing capacity depends on several factors. Horsepower and torque, transmission, differential gear ratio (4.10:1, 3.73:1, etc.) The higher the first number, the lower the gearing and higher the towing capacity. Your truck's GCWR (Gross Combined Weight Rating) should be on a sticker on the driver's door post. That number is what the loaded trailer and loaded truck combined can weigh to be safely towed. I hope that this helps you do the math.
2005 Cardinal Platinum 35 CKT
1999 Dodge Ram 3500 CTD Dually Crewcab with Lots of Mods.