I was hoping one of the standard owners (Kevin!) would chime in. I remember reading a write-up for a bypass filtration system for this standard. It would appear there must be a fluid pump if that is so, and I guess running it through a pre-existing cooler seemed like a good idea. Can you get under the truck and trace the lines - on the auto they're easy to trace back to the side of the transmission.
2 lines from it to the radiator. So this thing has a separate pump just for the trans? Go figure that must be why they recommend regular transmission fluid then gear oil in it. Either way it's probably safe to say I lost some fluid when I did the radiator switch. I need to check those levels out pronto.
The ZF-6 has a lobe type pump on the front of the countershaft (It's like a mini LPOP). Fluid is pumped from the bottom fitting to the tranny cooler in the radiator, then back to the upper fitting on the tranny.
A filter isn't a bad idea. I have a Magnefine filter Magnefine 3/8 Inch Magnetic Inline Transmission Filter plumbed in on the line from the tranny before it gets to the cooler. When you cut the line for the short hoses to install the filter, be sure to use a double flare tool and upset the end of the line so the hose won't slip off. I destroyed a tranny when that happened. Dumped all the fluid out and ate up the mainshaft.
One item I noted on your link is the location of the PTO cover. It's on the driver's side of my tranny, not the passenger side.
I heard people say it makes no difference on here, but from my recent experience I'm gonna have to say that Lucas has made my transmission shift much smoother. Added 2 quarts. Feels like easier power shifting and down shifting without clutch.... My 2 cents. I'm having a much more enjoyable ride with less grinding on my high mileage transmission.