(reposting this from my thread over on CVN with some minor edits)

Hi everyone. This past week I (finally) installed an inline auxiliary transmission cooler on my '03 Marauder. I figured some pictures of the install and some commentary would give anyone with a car that has the same stock cooling setup a head start

The first thing that I had to do was remove the electric fan and shroud. It is held in with 4 bolts and the fan connector.

Once that is done, the entire fan assembly should slide right out with a bit of finagling. It's a bit trickier with Marauders since the engine's size doesn't allow as much wiggle room for the reservoir - having an extra set of hands helped in my case. There is also a plastic arm that helps support the lower coolant hose that (to my knowledge) is only on Marauders. It can unclip from the rest of the assembly that'll make taking out the fan easier.

engine bay no shroud.jpg
I also removed the plastic deflector under the car.
lower rad hose 4v.jpg
The upper soft line coming from the transmission hardlines is what I unhooked first. I wanted to utilize the stock return soft line, so this'll be repurposed.
trans lines to hardline.jpg
The return line is the lower one as per the image below.
trans lines close up.jpg
A little bit of ATF will probably leak out so have a drain pan or some towels handy. I just used a random bolt to plug it.

I also unhooked it from the radiator side. This probably isn't necessary but since I was trying to find a good route to bring it in front of the A/C condenser, I didn't want to put too much stress on the hose from twisting it. This was a bit tricky since it is tight with the engine radiator on one side and steel bracketry on the other. The A/C accumulator's location on Marauders makes getting pliers on the spring clamp particularly difficult, but it is probably easier on 2v cars.
removed return line.jpg

As far as where the auxiliary cooler is located, I decided to set it about the middle of the condenser under the hood latch. No fancy brackets were made for this - I used the zip tie style straps that come with the cooler I used.
mocked up location.jpg
I routed the return line (going to the auxiliary cooler's inlet) this way. I didn't want it going below the stock radiator assembly nor over top, leaving this as the routing I chose.

It loops under the lower hose, going parallel with the frame rail.
route1.jpg
Then wraps around some A/C lines...
route2.jpg
And pops out behind this rubber cover behind one of these support beams that goes across the radiator. It helps when doing this to stick your hand through the rubber cover up front and stick the hose in from the back to bring it through.
route3.jpg
It's clear this will chafe in a few spots, so I used some wire loom to protect the hose.
loom1.jpg