DIY: Install ATF Cooler 2G MDX
 

Hello folks!


Well this is my DIY to install an Aftermarket ATF Cooler into our 2G MDX, this guide is similar to others like the Pilot or the Odyssey I just wanted to make a write up specifically for our MDX.

Background:
Now why you may ask? Why would we install an aftermarket ATF Cooler if our 2G MDX (12 or 13 I believe was optional?) comes with an OEM ATF Cooler?.. Well the answer is simple.. Our god damn radiator is a POS.... Yes the reason I installed an Aftermarket cooler was to bypass the Radiator ATF Cooler which is KNOWN to fail and mix Antifreeze into our ATF basically destroying the transmission.. There have been some people that have saved their transmissions because it suddenly slipped and they were quick to respond (Stop driving) but some other unlucky fellas haven't had the same luck. So I don't want to risk my luck and by pass it before its too late.

To the guide..
Now, I wanted to install a B&M Medium Sized cooler but after talking with a friend of mine that works in a trans shop he told me it would be just too overkill to add that specific cooler and our OEM in series. So he talked me down to a less efficient model that would not drop the temperature so much in the winter but by-pass the Radiator Cooler and be effective in the summer.
According to Him If I wanted to install the B&M Medium cooler I would have to by pass the OEM ATF cooler too! That good is the B&M Medium Cooler.

The unit I went for, is a Hayden 1404 TransSaver series.
Attachment 60744

Attachment 60745


This is the Unit itself, The camera lens cap is there for size reference:
Attachment 60746

Now the tools you will need for this job:
1.- ATF Trans Cooler (Your choice make sure isn't overkill, remember we have an OEM ATF Cooler, If your 12-13? doesn't have it then go bigger)
2.- Extra 4ft tubing, the included 4ft in the trans cooler isn't enough and the extra will work to unite both ends of the radiator cooler.
3.- 2x Tubing Couplers (To connect both ends of the tubes)
4.- Flat Screwdriver or Honda Plastic Push-In Clips Remover.
5.- 2x Extra Worm Gear Clamp that fits the size of the tubing.

Steps:
1.- Remove the Radiator Plastic Cover, They are all push in plastic clips.

2.- Remove the grille.. In the 07-09 you need to remove 2 push in clips on the top and 2 10mm screws, The grille is attached to the bumper by 4 push in clips. Remove those and the grille needs to be unclipped from the bumper.

3.- Use this picture for reference.. You will need to undo some 10mm screws so you can have play between the Radiator and Condenser for when you are installing the ATF Cooler.
Attachment 60747

4.- Remove the lower splash guard, Its held in place by several Push In Clips.. There are 4 below the radiator, 2 below the header, 2 on the far sides of the splash guard.

5.- Now this is the ATF Flow Diagram:
Attachment 60748

What we need to do is remove both ends of the Radiator Cooler IN and OUT and use those to feed the new ATF Cooler! This is not an easy task because of Honda STUPID tube pressure clamps which are always installed in the hardest angle ever... Work your way to remove both (Have a rag ready it will spit out ATF).

6.- Use the Tube Coupler to use the OEM Cooler IN as series for your ATF Cooler.. That end will be the one going out from your ATF Cooler. Then Feed the TRANS OUT to feed your new ATF Cooler.

You will need to tie both ends of the Radiator Cooler, This is to prevent future Anti-Freeze leaks if the Cooler decided to fail it wont leave you stranded. You can do this by using a single feet of tubing and connecting both ends.

This is the connection result:
I connected the Inlet for the ATF Cooler directly into the Trans OUT line so it will be cleaner
Attachment 60749

And the OUT of ATF Cooler into the OEM Cooler using the coupler.
Attachment 60750

You can see that the Radiator Cooler OUTLET Tubing is pinched? It doesn't matter that tube goes back to the Radiator Cooler INLET you just want to prevent Anti-Freeze leakage from those so tidiness is not necessary for that tube.

7.- Installing the ATF Cooler..
You can see the OEM Cooler here:
Attachment 60751

We want the new ATF cooler to be in the way of the airflow as much as possible, Due to the Grille and front bumper design 100% coverage is impossible so you will need to locate the cooler with as much airflow as possible.. This is my installation:
Attachment 60752

Attachment 60753

Airflow path:
Attachment 60754


8.- Once everything is tighten start the engine and check for any leaks! You will need to top off ATF because of the added displacement of the Lines and ATF Cooler. Its not much I filled about 1/4th of ATF quart.

9.- Install everything back together and enjoy!

Summary: Afer the cooler and a 100 mile steady 60mph trip in 58°F Outside the ATF Cooler was about 49°C the OEM Cooler was about 57°C which tells me about that efficiency difference between both.. So far I haven´t seen any lower numbers so its perfect! not excessively cool but not as hot as the OEM Setup either.

Hope this helps anyone attempting to By-pass the radiator cooler for future failure prevention.

How does the OEM ATF cooler mix oil into the engine antifreeze? It looks like it's a separate system altogether just like the one you just installed.

The radiator cooler joints breaks from the inside, allowing antifreeze to be sucked into the cooler thus to the ATF Lines into the transmission. There are some threads about the specific failure here:

Failure of transmission cooler inside of radiator (w/ pics) - Page 4 - Acura MDX Forum : Acura MDX SUV Forums

The vehicles in that thread all look like early 2000s models. In your excellent write up, the OEM cooler is the big unit on the front with the loop being the power steering cooler, correct? If the 2010-2013 has a separate cooler, I don't see how your modification changes the risks of anything if the system runs ATF from separate lines from the transmission directly to a dedicated radiator. Am I missing something?

The Power Steering Cooler is a big tube that goes on the bottom (EDIT: Can be seen in the OEM Cooler picture, That cylindrical tube on the bottom is the OEM Power Steering Cooler) the loop on top of the OEM ATF COOLER comes from the condenser lines, I dunno what is for.

Those Threads apply to the 2G MDX, Search for it on MDXers.org just about 2 weeks ago a 2008 failed in the same way that all the 1st gens Rad Coolers failed that guy was lucky, the trans started slipping 2 blocks from his house...

Seems that Honda used the same faulty radiator on the 2G MDX but somehow is less prone to failure (Not impossible though) since mine is a 07 is just too close to the faulty 1st gen years (05 & 06) so I expect to be using an old stock from those radiators.

Also.. The 2010-2013 models use the same setup, Difference being only that in some of those years the OEM ATF COOLER was being sold as a dealer installed option? I cant remember which year was it but anyway, That doesn't chance the issue being the RADIATOR COOLER which all years have.

The OEM Flow (With OEM ATF COOLER)
Trans > RAD > OEM COOLER > Trans

The OEM Flow (Without OEM ATF COOLER)
Trans > RAD > TRAS

The FLOW Now (By-passing the Radiator with Aftermarket cooler and OEM Cooler)
TRANS > ATF Cooler > OEM Cooler > Trans

The FLOW Now (By-passing the Radiator with Aftermarket cooler with NO OEM Cooler)
TRANS > ATF Cooler > Trans

I went ahead and test it on very steep inclines several times and check for temps.
(I will call the aftermarket cooler just ATF Cooler)

Max Temp: 78°C on the OEM Cooler and 69°C on the ATF Cooler.
That was doing about 5-10mph inclines about 35~45° angles this was to push the TC into heat oblivion but the coolers keep up just fine with little to no air flow.

Just for reference the "Transmission Hot" light comes up at around 95°C and the usual temp just driving in stop & go traffic for the OEM Cooler was about 71°C so doing inclines just make the oil heat up 7°C with this setup.

Awesome info!!! No longer bone stock 2G MDX :thumbsup:

Living in FL, we have no steep grades to climb, but how are you getting the temperature readings?

My trusty Fluke IR Temp gun:
Those readings are from the outside of the coolers not the actual ATF Reading. I need to add an In-line Temp gauge to get actual fluid readings but that is another DIY for another time.

BUMP!! Skirmich-I know this is probably in the instructions, but is there a direction of flow through the aftermarket cooler, like an input & output?, or can it go either way?
I need to do this mod to both my MDX & RDX to be safe.
If I am not towing anything with either vehicle, do you think the 1403 Medium Duty cooler will be adequate?

I think it all depends on you weather Alan.. I do not tow at all since I don´t have the hitch package but I went with a bigger unit because of our 110-120°F summers, So If you never see that kind of weather then sure the smaller the better because you don´t wanna get the ATF too cool or you "COULD" lose some MPGs and have slightly Harder Shifts. The main source of heat for the ATF is the Torque Converter so you cannot really get the ATF too cold unless you live in a really cold area.

There is no flow direction in that kind of ATF Cooler you can choose either as your input but as a rule of thumb I always choose the HOT on top like the radiator.

Damn, 110-120..that's desert hot!! We will have sometimes have a few days that break 100, but usual hottest days are around 95-100. We might hit 0 a day or 2 in winter, but most coldest lows are around 15-25.
I'm thinking the 1403 should be about right.
Did you run the little plastic mounting rods through both the radiator & condenser or just the condenser?

Just the Condenser but it was a PITA!! Be warned cuz you cannot lift the condenser out because of the A/C Lines, you just tilt it down.. What I did to help was to remove the top radiator supports so it could also tilt to the other side to leave a V shaped space between the both.. Getting to the lower rods its the real fun!.

I installed a transmission cooler & bypassed the radiator section in my RDX this past weekend. The only thing different from this great write-up is that the direction of flow in my RDX was the opposite to what Skirmich has for the MDX.
It was: Transmission to OEM cooler to radiator back to trans. I checked & tested this direction 3 times to make sure I was right.

This seems weird as I would think the radiator cooling section would be hotter than the OEM cooler since the radiator section is in the hot radiator. Seems like it would be better if the fluid went to the radiator first, then the OEM cooler. However, it doesn't matter now.

I plumbed it to go from trans to OEM cooler to aftermarket cooler back to trans. That way I could use the existing hoses from the trans to the OEM cooler & save a little work.
You weren't kidding about getting to those lower mounting rods-my wrist is bruised up pretty good from forcing my hand down between the radiator & condenser!!
Going to do the MDX next. I used the Hayden 1402 for the RDX and I will use the Hayden 1403 in the MDX.

Having the radiator portion at the last of the series seems kinda odd, I wonder why they went with this setup on the RDX?
Hahahaha I spouted some really nasty words when trying to fit my hands in there, Even worse was trying to fit my wire cutters to cut the excess rod and avoiding slipping them inside of there...

You missed a chance for a DIY for the RDX but In any case congrats and kudos for the work!

Sorry to bump an old thread. I am looking to do this into my 2005 RL just for the extra precaution. Would we all agree the Hayden 1401 would be a good choice??

Myself would go with a 1402 instead, The RL is in my opinion a Mid to Full Size sedan and SH-AWD is a big load on the trans so the 1402 sounds about right.. The 1401 sounds good for a TL.

Ok, so I haven't done this DIY yet, but may knock it out this summer on the MDX since last summer was so hot here in FL. Based on the above, I believe I have the OEM ATF cooler, so I should bypass the RAD and keep OEM ATF cooler? Routing would be trans > Aftermarket ATF cooler > OEM ATF cooler > Trans and no routing thru the rad, correct?

It looks like you had the OEM ATF cooler, but then deleted it.

No, I only deleted the ATF Warmer the OEM Cooler is still in series with the Aftermarket Cooler.
And yes the correct flow will be Trans > Aftermarket Cooler > OEM Cooler > Trans

I thought you were trying to avoid having the oem cooler routed in with the aftermarket cooler replacement? From your DIY, you remove the ends from the radiator but keep the OEM cooler routed in along with the Hayden cooler?

Yes both are working in series.. The point of doing this is to by-pass the ATF Warmer completely (The part inside the radiator) as that is the part that fails and mixes ATF/Coolant which destroys the transmission (Known defect of the early 2G MDX).

Both ATF Coolers help me here in So-Cali as our summers reach +120°F and I also do Off Road with the MDX...
Removing/By passing the ATF Warmer is common practice in So-Cali.

That helps a lot, Skirmich. I will be tackling this mod here in the next week or two and see where it goes. This is on my 2005 Acura RL. I will let you know if I run into problems.

Your welcome! if you have any questions feel free to ask.