Honda Repair: 90 civic tranny, quality name brand, timming belt

Question
my civic is downshifting hard from 2end to first,a little rough up shifting,its an automatic.i drained out the fluid(it was black)i replaced the fluid and its alot better but the downshifting problem is still there.is this hard on the timming belt? will draining the fulid agin and putting in honda fulid help or does it need to be rebuilt? thanks for any information you can give me.  

Answer
Lee:
If the fluid broke down, it may have done some internal damage to the transmission. You may want to change the fluid again, but I don't think it will make much difference if your transmission is going out. You do not need to use Honda fluid, using a high quality name brand will be just as good and a lot less money. This will not harm the timing belt.
Good luck.
Bill