SoO Trans cooler - Renix XJ (AW4) - Check my math

As some of you know I'm going through a big maintenance cycle trying to isolate, identify and fix all kinds of issues. I really want someone to check my math before I break something.

So I'm doing the spin-on transmission filter add-on as long as I had the transmission pipes disconnected from the radiator. Based mostly on this writeup: http://naxja.org/forum/showthread.php?t=1026658

However, I somehow managed to get completely confused as to which of the cooling lines is the hot, and which is the cold, probably because this isn't well documented.

The big thing I wanted to do was make sure the cooler lines are hooked up properly. The line that runs from the front of the trans comes straight out, which should be supply (I think), the line that comes from the rear of the trans comes up front, then dips underneath the oil pan.

I first hooked these up backwards and I was checking whether it was working by seeing if the filter got hot (implying warm fluid was flowing into it.) and it didn't. I just reversed it, and now the filter seems to be getting hot.

So just to make sure the line that comes from the front of the transmission, and comes straight off the passenger side is the hot side, and the one that dips underneath is the cold side?

Also, I wired it: trans->filter->cooler->radiator->trans

The line at the front of the tranny is hot out. The line towards the rear of the tranny is return.

I'm trying to figure out why it would matter which line the filter was in. Also, it IS well documented which is TO the cooler and which is RETURN.

It doesn't matter much. The only thing that comes to mind is if the filter is before the cooler it can help keep crap out of the cooler in the case of a transmission failure.