If the truck won't pull the load no one dies. Your rear gears will probably determine how hard it is to get a load moving but you should be able to move anything that is reasonable on a common dual axle car trailer.
But the real danger as others have suggested is stopping. And you are risking the lives of people around you if you can't stop.
If you are talking about hauling a frame or just some body parts and have trailer brakes and a good controller, you are probably okay.
In my state the law requires trailer brakes on any trailer over some number of pounds and which represent more than some percentage of the towing vehicle's weight. I'd suggest being sure you understand the local law and then make sure your configuration is well within the rules.
If you can't stop within a reasonable distance unload the trailer until you can.
