A lot of this is all semantics. All shops worth their salt use pressure filling systems, either bulk or batch, to fill transmissions. This could be something as simple as a hand pumped tank (batch) or pull down over head lines (bulk) commonly seen at larger facilities:

https://c1552172.ssl.cf0.rackcdn.com/354341_x800.jpg http://pictures.dealer.com/t/toyotao...d99aa5a55b.jpg

Both deliver the fluids under slight pressure, but just enough to get it into the transmissions. They are not flushing systems, but delivery systems. A pressure flushing system attaches to the external fluid lines on cars equipped with such lines, and push clean fluid through the transmission, pushing out the old fluid:

http://g02.a.alicdn.com/kf/HTB1DK6xI...pg_640x640.jpg https://w220.ee/images/thumb/2/20/72...on_Diagram.JPG https://i.ytimg.com/vi/8QcpnVOvQqA/maxresdefault.jpg

Pressure flushing systems operate at much higher pressure than the filling systems, but lower than the actual line pressures developed inside the trans when the car is running.

@ JFP in PA:

Thanks, now i understand what you've meant with pressure flushing. The MB ATF change systems work that way.

@nine8six:

Don't know what Porsche uses in detail to the job. The important part is to get all old ATF out of the system and refill it with new ATF and also to change the ATF oil filter, check all bearings and connectors. There is also an option to check all valves on functionality and to check the if the parameters of the transmissions gears are within specs.

@eliot92:

So in this case would do an electronic diagnosis first. If the transmission is within specs i would change ATF fluid completely and the ATF filter. If the transmission is not within specs you should what caused this. There are different valves, seals and filter sievs that can cause problems. Also the torque converter can cause problems. But i think that won't only affect 3. gear.

Regards, Markus