Transmission no reverse after filter and fluid change and not shifting right

Transmission was shifting fine and reverse was fine but oil was black. It did not smell burnt. Just black, so I dropped pan and did a fluid and filter change on it. Now it has no reverse will slowly move back if not on gas and it is not shifting right in the rest of the gears if I put it in first and shift it by hand into second it will shift but not in drive it revs to rev limiter and dose not shift what did I do? What can I do to fix it I used ATF plus 4.