I got my 7x16 enclosed trailer in. On Friday I bought a 94 Chev 1500 4x4, I hook it up and pull it down the high way and wow, I have to keep it in 3rd gear to keep 62mph. The truck has 5 gears (auto). This thing pulls like 3 tons of bricks. Not to mention the trailer is empty right now. Should it be this hard or is there a problem with my truck?