fluid dark or smell like anythin besides new fluid?
how many miles on it etc
try some seal conditioner
if no luck still then it may be time for another trans
seal ocnditioner is the first thi i add to any vehicle i get, i got 199k on my 91 s-10 700r4 original trans and it runs absolutely perfectly
i have never had a trans go bad on me using the stuff and ive owned driven over 100 different vehicles since 94, evne brought back some trannies that we thought were toasted with the stuff,