ATF cooler

[pvanv]

Seems any automatic trans could benefit from extra cooling, so I intend to add an air-to-oil cooler to our 05 xB. I thought I'd put it in line, ahead of the stock in-radiator cooler, so that it will dump maximum heat in summer, and yet the ATF will be warmed a bit quicker (by the antifreeze in the rad) in winter. Looks like I can mount it on the passenger side of the factory core support, where there is currently a "block-off" plastic plate. Thoughts?

[burstaneurysm]

Again, on a N/A 1NZ, you don't really need a trans cooler.

[pvanv]

I guess I'm just old school. All the old Detroit-based V8 cars of my youth ran the ATF a bit on the hot side. Seems the lovely little box has a really small AFT capacity. Plus, I am considering occasionally towing a small utility trailer. Frankly, I do not know the ATF temps as-is, so wasn't sure whether it was a good idea or not. I don't think it would hurt, as long as it is plumbed-in before the stock in-the-rad cooler (so the ATF doesn't get over-cooled in winter). Of course, it would add a quart of fluid to the overall picture, which shouldn't be a bad thing. Thoughts?

[burstaneurysm]

It certainly wouldn't hurt. They can be a bit of a pain to mount up. (We did a tranny cooler on my roommate's tC when he turboed).

Another thing is I hear would be turning off the O/D when pulling a trailer.

[pvanv]

I have decided to use a trans cooler on our 05 xB, since it won't hurt when towing the utility trailer, and it will add a quart or so of ATF to the system. Then comes the issue of where to mount it, and how best to plumb it.

When I have installed trans coolers in the past, I normally plumb them in line, feeding the trans fluid through the new cooler first, then through the factory loop (in the radiator). The reasoning is that on really hot days, this allows the aftermarket cooler to receive the hottest fluid, so it can dissipate the most BTU's. Also, on cold days, it will allow the factory loop to pick up heat from the antifreeze (as the fluid goes back to the transmission), so that warm-ups are a little quicker, reducing "over-cooling" of the ATF.

I think I will mount the trans cooler on the passenger side of the core support (where there is a factory block-off plate of sorts). This way, the rejected heat is not in the in-line airflow for the a/c condenser and radiator. So both the the trans cooler and the other 2 "radiators" will be the most efficient at dumping heat. Also, since this is not in-line with the electric fan, there should only be airflow through the cooler when the xB is in motion -- when the cooling is needed the most, and it won't make a huge "sandwich" with the fan, radiator, and a/c condenser.

That said, my quest is to find out which of the trans fluid cooling tubes flows which way -- in other words, which tube flows to the radiator, and which is the return to the transmission? I tried looking through the online manuals. It isn't clear (to me). Which tube is which?

Anyone know?

[pvanv]

I'm ready to install the cooler this weekend, but the question remains: Which tube flows to the radiator, and which is the return to the transmission? I suppose I could just cut a tube and start the motor, and see which way the fluid flows...