I have a 5000 lb camper, I only towed it once, due to a bad alt. But I had no problems I had an electric brake controller, I would guess going up hills that would be a small problem. before I tow it again I will be installing a transmission cooler and changing the trans fluid, but I need to check on the trani fluid type, I read somewhere that you might need to use just toyota trans fluid, but I think that was on the newer 4Runners that have no dip stick, I drive a 2003 4x4 v6 sport edition, easily the best 4Runner I have had, out of about ten a few of each gen.:awais: