If your filter was that bad, you could have some other stuff floating around inside the tranny. Before taking the leap into the money pit, I would change the filter and fluid again, adding a trans conditioning additive. Run it about 500 miles, drain and change again. Make sure you also drained the convertor as well That component holds a ton of oil. It does no good to drain the pan and leave half the oil capacity of the tranny in the converter. Good Luck..
1987 BMW 325