I tow al kind of thing all the time. My 3.5 Work Truck just turned 100, 000 miles. up to 3,00 or 4,000 pound you will ever notice the weight. My heaviest thing is my Diesel John Deere on a dual axle trailer. Together they weight 9,300 pounds (with the back hoe installed). I just unloaded and disconnected the trailer today this afternoon. This the time of year where I go around and roto-till all of my friends' gardens for them. If loaded properly, you will not notice the weight in semi-flat land country.
What you will notice is towing big items with flat front surfaces. Large single or dual box trailers or large front surface campers.
Two comments.
Tow in 3rd gear if you notice a lot of automatic transmission down shifting. My heavy tractor or a trailer does not have a lot of front surface area and does not cause this, but a much lighter empty box trailer sure causes the shifting problem.
If running much over 3000 pounds, install a trailer brake controller. If the trailer is commercially made and has brakes then install the controller. States vary in their weight requirements for trailer brakes but even if your state does not require it, I would install brakes on the trailer if it is over 3,000 pounds loaded.