My 92 is slow to shift from 2nd to 3rd. Is there a filter in a four speed automatic trans? I had the fluid changed but I think they sucked it out.

There is a screen inside the transmission. You need to remove the cover to replace it.

When you say "slow" do you mean it takes a while to complete the shift or does the engine rev higher than expected before it shifts?

The engine revs and stays in the lower gear longer that it should.