Transmission not shifting properly

My car shifts fine when cold or hot, and will run down the interstate perfectly. It dose not downshift hard or shift hard go from a stop all the way through drive. The problem I am having is when I try to push the gas down and accelerate hard the trans acts like it is slipping. If I let up off the gas and it settles I can push the gas back down at a normal range to drive it is fine. What could be my issue? The transmission fluid is at normal level and has no fowl burnt smell to it. The trans dipstick was not sealing properly and was just flopping around apparently like most of these years of Honda's do. So I purchased a new one but I am still having the same issue, it will not kick in the passing gear without acting like it is slipping. Like I have said easier the car will run seventy plus on the interstate and run just fine on the back roads when driving normal, just will not accelerate real hard when the gas is pushed down to pass someone. Any help would be appreciated.