90 honda accord ex automatic transmission problems

I have a 90 accord ex that has around 202,000 miles on it. When the car is driving at half throttle it runs great and shifts fine. But when I push the pedel down to more than 3/4 throttle the tranny wants to shift iraticly from 1st to 2nd then back to 1st and so on, no matter what speed I'm going. I wanted to change the filter for the tranny but there is not an external filter on it. I was told that it has an internal filter that in order for it to be changed I need to split the tranny? Whould this even help my problem? The fluid level is at a good level too.
Don't worry about this one guys! I'm selling it now so screw it! Thanks though!
Manufatures are cute - they call their cars "tranverse engines" ------- I WILL NEVER!!!!! OWN ONE! They are very popular and if buying new consider the extended warranty. Otherwise I consider this crap a square wheel and buyers beware!!!!! Just my opinion, do what you want! Tom