Yes, you're overloaded.....but (I'm assuming) you bought the trailer you really like. Trade in the truck on something that will pull it safely, even if you have to go used. Any good modern 2500 will get the job done safely. Don't lower the water....raise the bridge. As for being OK towing it on flat, short trips....
don't. If you have an accident and it's determined by the other's party's attorney(ies) that you knowingly and intentionally towed with an overloaded vehicle, there could be civil and even possibly criminal ramifications. And if you think their attorney(ies) won't find this post online......
But that is secondary to the safety of you and your family. If you get a nasty crosswind and the trailer drags the truck into a ditch, it won't end well. What if you blow a tire on the trailer? Can your 1500 control it, even on flat land....or will you just be along for the ride. And then there's the subject of braking....which my friend Tony (Who, BTW, loves my Cummins) addressed....and I gave a counterpoint.
TonyDtorch said:
it's not the truck that stops a trailer..... the trailer brakes do most of the stopping.
Until a wire gets pinched, grounds, and blows the fuse. Now you have ZERO trailer brakes. This will happen at the most inopportune time....like coming down a long, twisty 10% grade with nowhere to pull off. Yes, it CAN happen....and if it does, you need a truck substantial enough to keep the trailer under control.
Finally, don't feel bad. A lot of us have made goofs regarding safe towing weights when we were rookies at this. And the salesperson is a charlatan.....especially if he owns the dealership. He intentionally put you at risk to make a buck. He knew damn good and well that the trailer was too much for your tow vehicle, and yet he talked you into buying it. He could have told you that, and found you an alternative that was within your truck's specs. So to answer your original question, yes....you got lied to. That isn't your fault, so don't kick yourself. Call the dealer and tell him what you've discovered. Show him this thread if you want to....if he has a problem with me referring to him as a charlatan, he can call me and I will explain to him why he is just that.