Horse Trailering Problem

Hello, I am new to horse forum.
I have a 8 year old quarter horse gelding and he picks things up fast but can be pushy. I recently bought a three horse angle haul that has lots of room, its not a dark color and he does not find it scary. He will walk right in, stand there for a bit then all of a sudden will back out really fast and when I tie him he pulls back and I am scared he will hurt himself or someone else! Please help!

My mare used to do the same thing. Monty Roberts, an AMAZING horseman, has a lot of videos on this. I tried his methods with both of my horses, and they were much better at loading AND backing off of the trailer.

Click to see one of his videos.

You may want to try letting him turn around in the trailer IF there's enough room. I have a 2 horse slant trailer and it's enough room for my 16h TB mare to turn around in.