4l60e high rpm little movement

I have a automatic transmissionthat was not functioning all of a sudden I drop the pan and found that fluid was very dirty the car before would reach very high RPM's especially in reverse and only moved about 5 miles per hour when at 3000 rpm and forward it was sluggish as well the first thing I did was drop the pan and change fluid fluid was very dirty but found no other debris put new fluid and car drove perfect like brand new for about 80 miles and then problem started happening again dropped pan once more figured new filter got plugs fluid was dirty again and dark no burnt smell just dirty change fluid and filter and expected car to work again but it did not I hear it no sounds or whining when car is in geare or in neutral. problem seems to be worse in Reverse I have checked fluid levels and they are fine check engine hot ran through all the Gears. check to see if we win level changes when engine running and it does so I believe the pump is OK I have no idea what is going on when it failed on the road it was running fine and then suddenly seemed like RPM's works tremely high with no power

sorry for the odd post using my phone's text to speech I mean speech to text I posted that the RPM's run very high but engine power drops and that I do not hear any whining sounds from the car when in gear or neutral and that I checked through it levels when engine hot ran through every gear

Well you didn't give what year. Friend issues similar. Partially plugged cat.

1999

You're gonna need to run it to a tranny shop and pull codes.