2004 Focus Wagon, Zetec DOHC, Auto
Agree and disagree on certain points here. I think a clogged filter is what was causing the "3rd gear lurching" after being warmed up.After one time to check initial trans run-in I have pretty much gone to not changing filters every time as they simply do not clog up. A drain plug in pan then makes it the work of five minutes to drain fluid but only the partial amount not all of it. It seems to be enough, the ATX on 3 cars now done like that and no trouble from them at all, one is at 200K miles. The other two at 150K. Maybe drive car a week and change fluid again to get a higher percentage of new and save the drained fluid there for the chainsaw, it makes great bar oil. And even more money made.
After changing filters on ATX on cars for like years at the garage you come to the conclusion they really don't need it unless something is going wrong in the trans. The steel screened ones are even easily cleaned to go right back on car, I've done that as well. Fuzz type filters I'll change based on the amount of grey grime there, but if careful you can even clean them, I've done it. You certainly don't need to do it every time. Maybe every other if you will. Had the idea forever but the CD4E in a Contour and having to yank trans to change that filter convinced me to start doing it.