2019 CX-5 Diesel Aftermarket Transmission Cooler

⋯ More aggressive than the currently recommended 30K mi interval? Or does that suffice?
Mazda has never had an ATF replacement schedule in their Schedule 1 (normal driving conditions) and Schedule 2 (severe driving conditions) maintenance. They claim the ATF is lifetime.

On gen-1 CX-5, there’re a couple of notes, *5*6, for rear differential oil; and a note, *6, for transfer oil on maintenance schedule:

*5 If the vehicle is operated primarily under any of the following conditions, replace the rear differential oil at every 48,000 km (30,000 miles).
a) Towing a trailer or using a car-top carrier
b) Driving in dusty, sandy or wet conditions
c) Extended periods of idling or low speed operation
d) Repeated short trips of less than 16 km (10 miles)
*6 If this component has been submerged in water, the oil should be replaced.


But for gen-2 CX-5 both rear differential oil and transfer oil have only one note, *4, on maintenance schedule:

*4 If this component has been submerged in water, the oil should be replaced.

So if I were you, I’d replace ATF in transmission、gear lube in rear differential (might as well the front transfer case) at 30,000 miles like ColtX-5 has been doing (unless I haven’t been towing within that period).
 
Update for everyone here:

1. Appointment has been scheduled after this weekend for the replacement of ATF, gear lube in rear diff and front xfr case with the dealer. I am not mechanically inclined, so I hope they will do a better job than I. My plan is to tow after this is done and to post the results of tranny/engine temps post-servicing.

2. I have been in touch with a gentleman who mods/customizes transmissions. I have an appointment booked in with him in the last week of July where he will have my car for a week and will look to see about machining a custom solution for a transmission cooler.

I will report back after all these events occur. Hopefully it's good news/good results all around.
 
Now that you report this, I do find the temps differences quite significant; however, note that when I got the high temps, the outside temperature with humidity was about 32C or 89.6F... So I don't know what temperatures you were towing in. But I ensure to do all of these things to remain safe and to preserve the vehicle.

That's why I mentioned the trip to OH, through the mountains of E. KY. I don't remember the grade slopes, but there were lots of them and the temps were mid-80s with the A/C on, I pull an R-Pod that is somewhat aerodynamic, but not enough to need brakes downhill.
 
That's why I mentioned the trip to OH, through the mountains of E. KY. I don't remember the grade slopes, but there were lots of them and the temps were mid-80s with the A/C on, I pull an R-Pod that is somewhat aerodynamic, but not enough to need brakes downhill.
Apologies, I'm not as proficient with my US geography as I'd like to be. This was part of why I wanted a TT: to explore the neighbourhood to the south. I pull a Jayco Swift 184BH that I pack judiciously (to my wife's chagrin) to ensure we are underweight.
 
I looked at those, several times, nice, but finally decided the bunks were wasted space and bought an RP-180.
 
I am amazed you are seeing those kinds of temps. With my '15 I don't really see anything above 205 on grades towing trailer. I normally use OBD Link but same results with Forscan in the past. I'm towing tomorrow so will try to track some graphs.

I'm not sure there is a parameter to track by I track AT lockup in my other vehicles. If I can keep in lockup temps down they don't spiral upward.

I regularly drive over mountain passes.
 
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I am amazed you are seeing those kinds of temps. With my '15 I don't really see anything above 205 on grades towing trailer. I normally use OBD Link but same results with Forscan in the past. I'm towing tomorrow so will try to track some graphs.

I can't reiterate how grateful I am of people like you, ColtX-5, et al. who are actually providing helpful information. I tried asking a similar question in other social media platforms and I usually get attacked by the weight police or people telling me I need a truck.

I'll also take this opportunity to provide a quick update:

1. Towed the other day and I'm still getting temps around 230-235 F with outside temps of 29-32 C (84-89 F). I was really taking it easy and I was happy to not see 240-250 F this time around. Still a little high compared to what others are reporting.

2. The local dealer quoted me over $1200 CAD for the replacement of all the fluids. So I'm flipping them the bird and getting the gentleman who is going to be modding my transmission to accept the cooler to do all of the work on top of everything. I have also since found out that the gentleman (the owner himself) takes all the vehicles he works on for test drives himself. It's a good sign that he's going to be willing to tinker until things work out... Or maybe not. I am anxiously waiting for Monday to roll around.

Edit - Forgot to mention (and people keep asking) - I measure my transmission temperature with an Ultragauge.
 
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I was all set with gauges on OBD link today and while monitoring I forgot to enable logging.... ggrrrrr.

I was only towing around 1500-1600lbs today and pretty much let the AT do it's things. Even on long leg up to summit and keeping it at 70MPH she kept a steady pull in 4th @4K RPM. AT temps never exceed about 203.5 °F. Outside temperatures weren't really hot though... it was morning at 60 degrees.

That adapter would probably have to be purchased from a BG Products dealer.

PN: PN TF832116QC

 
I was all set with gauges on OBD link today and while monitoring I forgot to enable logging.... ggrrrrr.

I was only towing around 1500-1600lbs today and pretty much let the AT do it's things. Even on long leg up to summit and keeping it at 70MPH she kept a steady pull in 4th @4K RPM. AT temps never exceed about 203.5 °F. Outside temperatures weren't really hot though... it was morning at 60 degrees.

That adapter would probably have to be purchased from a BG Products dealer.

PN: PN TF832116QC

“To perform a BG Transmission Service on 2011 and newer Mazda vehicles with SkyActive drivetrains use the new Mazda Transmission Adaptor Plate, PN TF832116QC. Move the round transmission cooler to the side and replace it with PN TF832116QC.”

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The only problem by using this ATF service adapter is you have to keep the original round ATF cooler around with no usage of cooling the ATF. The best is to find a modified ATF cooler available for many CVTs with 2 extra ATF ports.


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There are some fairly high capacity external close circuit (AT fluid only) coolers these days that even have extra fans attached to them. This would be a good test for someone. I've never heard of this happening on any Skyactiv Mazdas but you would reduce the possibility of cross contamination failure or a milkshake condition of mixed AT fluid and coolant.

That may really not be possible with this stock cooler... if it is overbuilt

I've not seen one cut in half. If anyone has a picture that would be interesting to see.

These coolers from Australia used in overlanding applications unfortunately may overcool. I really haven't looked to see what kind of space there is to mount an external cooler.

 
Update - All fluids changed and aftermarket cooler is installed. For the cooler, an adapter was machined out of aluminum and a cooler fit onto it. The OEM cooler then sits over it. Same idea mentioned by yrwei52. Mind you, I'm not an expert at this, but the shop sent me a cellphone video of what they machined. You can have a look at what it looks like. So far, without towing, temps around 170-160 rather than the 180. I am going on a week long trip out of town (560 km or 347 miles) and will be towing for about 2-3 hrs at a time. I will keep an eye on the temps and report back then.
 

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Ironically.. BG Products corporate wants me to call them back about that fluid flush adapter for sale to retail customers. I'll find out how easy to obtain after I get back into a town in a few weeks.
 
I am amazed you are seeing those kinds of temps. With my '15 I don't really see anything above 205 on grades towing trailer. I normally use OBD Link but same results with Forscan in the past. I'm towing tomorrow so will try to track some graphs.

I'm not sure there is a parameter to track by I track AT lockup in my other vehicles. If I can keep in lockup temps down they don't spiral upward.

I regularly drive over mountain passes.
Curious, what's the outside temp when you tow? I don't tow and my trans temps are around 207 when I go up a mountain, outside ambient temp was around 92 F after driving 15 miles.
 
Update - First tow completed. It's a scorcher here today...With humidity we are at 37 C or 98 F. Although the engine got to 202 F, the tranny went up to 212 and floated there after an hour or so. Tomorrow is the second leg and we will be going for about 2 hours or so. I will post an update when this trip is over by the end of the week but it's looking good so far.
 
My outside temps during towing usually range 40-85 degrees.

Curious, what's the outside temp when you tow? I don't tow and my trans temps are around 207 when I go up a mountain, outside ambient temp was around 92 F after driving 15 miles.
 
Post Trip Update:

Just finished my 1700km (1056 mile) trip between Ontario and Quebec City. And of course, there was a heatwave during the trip, so ambient temperatures ranged between 27-38 C (80-100 F). I will insert a disclaimer here that none of these numbers are scientific in anyway and just based on my observations, so YMMV. Driving style was adjusted to my load (3100lbs Jayco 184BH travel trailer) and I was following the speed limit or slower throughout: 95-100kph (59-62 mph). Alright, so here are my findings:

1. Ambient temperatures of 27-30 C (80-86 F) during overcast resulted in transmission temperatures of 209-215 F (98-102 C).
2. While in direct sunlight with 27-30 C (80-86 F) transmission temperatures were 212-218 F (100-103 C).
3. On the harder end, while climbing hills and/or when ambient temperatures were up to 30-38 C (86-100 F) the transmission temperatures rose up to 218-222 F (100-105 C).

After towing all that distance, I can say that I have no issues to report. Moreover, probably the most positive surprise was the fuel economy of the vehicle - average of 13L/100km or 18 MPG.
 
Post Trip Update:

Just finished my 1700km (1056 mile) trip between Ontario and Quebec City. And of course, there was a heatwave during the trip, so ambient temperatures ranged between 27-38 C (80-100 F). I will insert a disclaimer here that none of these numbers are scientific in anyway and just based on my observations, so YMMV. Driving style was adjusted to my load (3100lbs Jayco 184BH travel trailer) and I was following the speed limit or slower throughout: 95-100kph (59-62 mph). Alright, so here are my findings:

1. Ambient temperatures of 27-30 C (80-86 F) during overcast resulted in transmission temperatures of 209-215 F (98-102 C).
2. While in direct sunlight with 27-30 C (80-86 F) transmission temperatures were 212-218 F (100-103 C).
3. On the harder end, while climbing hills and/or when ambient temperatures were up to 30-38 C (86-100 F) the transmission temperatures rose up to 218-222 F (100-105 C).

After towing all that distance, I can say that I have no issues to report. Moreover, probably the most positive surprise was the fuel economy of the vehicle - average of 13L/100km or 18 MPG.
Have you ever touched factory ATF when you added the ATF cooler adapter? Or have you ever checked the factory ATF level? And have you even done any ATF drain-and-fill so far?

With added external ATF cooler, I’d imagine you need some additional ATF FZ (0000-FZ-113E-01) to keep the ATF in correct operating level.
 
Have you ever touched factory ATF when you added the ATF cooler adapter? Or have you ever checked the factory ATF level? And have you even done any ATF drain-and-fill so far?

With added external ATF cooler, I’d imagine you need some additional ATF FZ (0000-FZ-113E-01) to keep the ATF in correct operating level.
A transmission service (ATF drain and fill, rear diff/front xfr fluid change) was all done in addition to the ATF cooler install. I'm good for at least another 30K miles / 48K km.
 
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