i was towing my 2 place sled trailer with 2 atvs on it, about 2400 pounds. I was hitting a very strong head wind, so i had O/D off and just stayed around 65. The rpms were around 2600-2700, but sometimes when i was climbing a hill, my rpms would slip uo to about 2900 for a second, then go right back to normal. It only did this while climbing a hill. My question is, is this normal for the trans to do that? It only did it 2 or 3 times

It just sounds like your converter was unlocking. Nothing I would worry about.

Mine does the same thing when I am not towing, just the hilly land!