Guide: How to install Auxiliary AFT Cooler (2008-2010 Mazda5)

[flcruising]

I had a number of replacement parts and upgrades to do to this vehicle today. They included installing something myself and others have been talking about doing for a loooong time - an auxiliary transmission cooler. Well, I finally did it, and here you go. Before we get started though, here is the whole spread of items that I tackled in the scorching heat and humidity.

Since I was removing the oil cooler for sanding/painting because it exhibited more rust than I was comfortable with, I also decided to do the spin-on oil filter conversion. And since removing the oil cooler required draining the antifreeze/coolant, I decided to replace the thermostat. Therefore this project kinda snowballed, but here I will focus on the ATF cooler.

First thing you need to do is choose a cooler to satisfy your needs, for me it was the https://www.amazon.com/dp/ (commissions earned). Since we plan on purchasing a camper of some sort this year, I wanted a larger cooler. This cooler comes with about 4' of 11/32" hose, you will need another 4' from your local auto parts store. I chose to use fuel line hose clamps too, because I don't like worm gear type, about $2.50 from AutoZone.

First remove the front bumper cover, I followed this guy's very helpful guide. 10 minutes tops to get it off.

I had also purchased some aluminum bar angle and stainless steel hardware because I anticipated mounting it securely to the radiator core support, but since this structure is fiberglass composite and irregularly shaped, this didn't work. The solution I came up with was to drill 2 small holes (1/8") in the lower support, pop up the radiator and condenser and insert 2 of the zip-ties that come with the cooler through the holes from the back. This supports only the bottom of the cooler, but the hoses zip-tied in place secure the top adequately.

*The best route for the hoses is under the driver's headlight.

*You also have to remove the airbox to get to the transmission for connecting. My choice was to have the AFT outlet line feed the new cooler first, then to the stock heat exchanger, both in series. This should help to not over-cool the fluid in cold weather.

 

[Silentnoise713]

As request, changed title to reflect years but I suspect it is likely the same.


Awesome post btw but we want more details! 


I'm not even sure if I need the cooler at this point b/c I've been very happy with just the complete flush + Amsoil. My biggest challenge is how/where to physically mount the aux cooler. It's a tad smaller and would need brackets/extensions to fit, it can't reach two sides . Have you also though about adding an external transmission filter? From some of the cut-outs I've seen on BITOG, they do an admirable job!

 

[Vasy]

Have you also though about adding an external transmission filter? From some of the cut-outs I've seen on BITOG, they do an admirable job!

Can you post a link to those filters?

 

[flcruising]

I was doing a drain/fill every 5k with oil changes, but I'm hoping this will keep me from doing them but every 100k now.

What kind of details?

I hear what you're saying about the brackets because I tried to do this with the aluminum angle and there just wasn't anything for 2 cross bar supports to attach to. For me just drilling two holes in the bottom radiator support for a couple of zip ties was adequate. In this attachment, the 1 zip tie holding the supply hose to the upper Y arm was enough up top.

If you decide to use a shorter cooler, then you could probably have some support brackets below the crash bar, but with the 678 being so tall, I would have had to remove the thing to get holes drilled. And that was NOT going to happen.

 

[Silentnoise713]

Can you post a link to those filters?

https://www.amazon.com/dp/ (commissions earned)

From what I recall, both the Magnefine and WIX are rebrands with the Magnefine being the slightly better one and slightly larger; I have both in hand. Super easy to installed. Simply cut (or use new hoses) the tranny case outlet to cooler hose and put this puppy in-between (says the guy who hasn’t installed it yet).


You can also get fancy and go the external filter route.
https://www.amazon.com/dp/ (commissions earned)

I was doing a drain/fill every 5k with oil changes, but I'm hoping this will keep me from doing them but every 100k now.

What kind of details?

I hear what you're saying about the brackets because I tried to do this with the aluminum angle and there just wasn't anything for 2 cross bar supports to attach to. For me just drilling two holes in the bottom radiator support for a couple of zip ties was adequate. In this attachment, the 1 zip tie holding the supply hose to the upper Y arm was enough up top.

If you decide to use a shorter cooler, then you could probably have some support brackets below the crash bar, but with the 678 being so tall, I would have had to remove the thing to get holes drilled. And that was NOT going to happen.

More pics would be great to see how/where things go, especially for those who haven’t seen it before and want to do this. When I think of a how-to, I imagine a layman’s guide. I still can’t believe you are the first (from what I recall) to actually do this when we all know the AT is a weak link!.

IMO, full flush with quality fluid + cooler + external filter will last longer then a typical owner will keep the car.

 

[flcruising]

I'm sorry I didn't take more pictures. I just had so much to do that day that I didn't even set out to do a "How-To" of this (as you can tell). Hopefully the larger photos will help.

It really was not hard at all once I determined that the aluminum support bar wouldn't work. My other vehicle has just regular zip ties holding it to some existing holes similarly. The push-through type that come with most coolers I would NOT recommend installing as described by the manufacturer if you intend on keeping the vehicle. They tell you to push them through the condenser/radiator and attach the cooler to the front with some foam pads. The foam pads wear out. After a few years my other car's condenser had some nice holes rubbed through on it that took some work to fix, twice. Both of my vehicles now have auxiliary coolers installed in front and independent of the condenser/radiator.

 

[Secondtyme]

Give us numbers dammit! Before and after on fluid temps or it didn't happen! LOL Good on ya for doing this, you have encouraged me to go for it myself. I have thus far not seen trand fluid temps higher than 207 degrees, this in dead of summer, AC on, in traffic. I imagine with the stock heat exchanger still in play, you'll be about 185-190 in normal use. And BTW, get that damned intake tuba out of there STAT!

 

[flcruising]

How do you monitor transmission temperature? Do you have the PID?

 

[Robotazky]

Great post, Aaron. Thanks!

 

[Silentnoise713]

Give us numbers dammit! Before and after on fluid temps or it didn't happen! LOL Good on ya for doing this, you have encouraged me to go for it myself. I have thus far not seen trand fluid temps higher than 207 degrees, this in dead of summer, AC on, in traffic. I imagine with the stock heat exchanger still in play, you'll be about 185-190 in normal use. And BTW, get that damned intake tuba out of there STAT!

Did you get this number from an UG or SG2?

Below is just a general guide but the idea is that a 10-20 degree difference matters a lot. The threshold will differ depending on the quality of the fluid, etc.
http://www.northernautoparts.com/Images/Uploaded/TCI/trans_life_expectancy.jpg


Overcooling is really only a concern on startup and the first few miles/minutes. I haven't seen any concrete evidence where this is a real concern, only speculation. It boils down to need. If you plan on towing with this car or hot climate, I would say an aux cooler is highly recommended. Otherwise, just be mindful of your fluid life.

@ Flucrusing – The Hayden you have looks identical to the B&M I have. Do you know how many BTU it is rated for?

 

[Secondtyme]

All my numbers are via SGII. Yes I am aware that a couple degrees can make all the difference in the world. My thoughts on an aux cooler have so far been that if it is easy, and cheap enough, extra cooling is good insurance against the trans fluid baking tendencies of our 5s. I will be adding the very same model to mine before this winter, mainly based on flcruisings photos, which tell me that it really isn't a big deal. Incidentally, I'm going for the canister conversion at the same time LOL.

 

[Antoine]

Thanks for posting this guide back in 2013. Added it to our Resources section...

Resources

www.mazdas247.com