I had rough transmission shifting up and down after a shop that replaced the solenoid pack put 4 qt of the wrong fluid in there. I dropped the pan changed the filter replaced the fluid then pulled a cooler line and pumped out another 4 quarts of fluid and replaced it. I think it got 7 to 8 quarts of new fluid overall doing this. The tranny operated like brand new immediately.
That was about a month ago. After a week of smooth shifting, it started to get rough again up and down and now it is like before but not quite as bad.
Question; would this be caused by the new fluid mixing with old fluid left in the converter (and any other areas I couldn't drain)?
If so what is the remedy? Remove the pan again and do the same procedure over (less the filter), or should I just pump some more fluid out of the cooler hose?
Thanks for input in advance.
Gary