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I was thinking about adding the transmission cooler to my Passport, i.e. a cooler transmission equals longer life. Then I had a conversation with a mechanic buddy at the local diner recently, he suggested not to install the separate transmission cooler. He said, in many other vehicles with an automatic transmission the transmission cooler is placed inside the car radiator. The car radiator provides temperature regulation, i.e. it warms the transmission up when it is cold and keeps it from getting too hot. There are a lot of very sensitive parts and tolerances inside a modern transmission. I can see driving in a frigid Ontario winter, with the separate cooler keeping the transmission ice cold all day. And separate coolers only work by air flow, compared to a cooler inside the car radiator, which again is in a temperature controlled environment. Does any one have experience with this issue? Am I missing some detail, like the transmission has a thermostat or something? Are there any other Honda models with the transmission cooler in the radiator? And too bad the manufacturers don’t have a transmission temperature read-out; based on the level of technology in this vehicle, it could easily be programmed to record and send the temperature history to your phone.
 

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1. The transmission cooler is not in the radiator, it looks like a mini radiator that sits bolted to the vehicle's frame just in front of the radiator to access air flow.
2. It's job is to keep the temperature of the transmission fluid from getting high enough to damage the transmission, it won't keep the the transmission ice cold even in Ontario.
3. The transmission cooler is compulsory if you intend to tow trailers up to 5,000 lbs, else you do not need to install it.
 

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I was thinking about adding the transmission cooler to my Passport, i.e. a cooler transmission equals longer life. Then I had a conversation with a mechanic buddy at the local diner recently, he suggested not to install the separate transmission cooler. He said, in many other vehicles with an automatic transmission the transmission cooler is placed inside the car radiator. The car radiator provides temperature regulation, i.e. it warms the transmission up when it is cold and keeps it from getting too hot. There are a lot of very sensitive parts and tolerances inside a modern transmission. I can see driving in a frigid Ontario winter, with the separate cooler keeping the transmission ice cold all day. And separate coolers only work by air flow, compared to a cooler inside the car radiator, which again is in a temperature controlled environment. Does any one have experience with this issue? Am I missing some detail, like the transmission has a thermostat or something? Are there any other Honda models with the transmission cooler in the radiator? And too bad the manufacturers don’t have a transmission temperature read-out; based on the level of technology in this vehicle, it could easily be programmed to record and send the temperature history to your phone.

Your friend is correct. My friend owned two transmission
I was thinking about adding the transmission cooler to my Passport, i.e. a cooler transmission equals longer life. Then I had a conversation with a mechanic buddy at the local diner recently, he suggested not to install the separate transmission cooler. He said, in many other vehicles with an automatic transmission the transmission cooler is placed inside the car radiator. The car radiator provides temperature regulation, i.e. it warms the transmission up when it is cold and keeps it from getting too hot. There are a lot of very sensitive parts and tolerances inside a modern transmission. I can see driving in a frigid Ontario winter, with the separate cooler keeping the transmission ice cold all day. And separate coolers only work by air flow, compared to a cooler inside the car radiator, which again is in a temperature controlled environment. Does any one have experience with this issue? Am I missing some detail, like the transmission has a thermostat or something? Are there any other Honda models with the transmission cooler in the radiator? And too bad the manufacturers don’t have a transmission temperature read-out; based on the level of technology in this vehicle, it could easily be programmed to record and send the temperature history to your phone.
Read the article I linked.Your friend is correct about an isolated transmission cooler in colder climates. I own also own a 2011 Ford E250 work van with the towing package installed from the factory, it has an additional transmission cooler that is connected in series with the one in the radiator tank. This allows for the transmission fluid to warm up as the vehicle warms up. Personally, I do not understand why Honda doesn’t have a transmission cooler in the radiator tank. I have a friend that owned two transmission shops here in the Northeast and the preferred method of installing an external transmission cooler was in series with the one in the radiator.
 

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The transmission cooler is an option that Honda offers (about $1,050 installed) and it is attached to the front (lower driver's side) of the radiator. The OEM option is designed to be the correct size (BTU) to not allow over cooling of the AFT fluid, which can lead to issues.
 
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Let's clear up the terms.

The radiator, which has coolant in it has a separate compartment with ATF-Type 3 fluid in it. This compartment's temp is regulated by Honda computer that monitors the coolant's temp. If the coolant is too hot a radiator fan is turned on. If the compartments ATF is too hot, it will cause the Coolant to increase its temp and the fan will turn on.
Older versions of this dual tank set up is found on many Hondas/Acuras and the only one that has had an issue was the 2007 - 09 Acura MDX, after 15 years of service. The two tanks would rust thru and allow the ATF-DW-1 to mix with the coolant and destroy the tranny, but forums like mdxers dot org helped owners pre-emptively address the issue.

The transmission cooler is an option that Honda offers (about $1,050 installed) and it is attached to the front (lower driver's side) of the radiator. The OEM option is designed to be the correct size (BTU) to not allow over cooling of the AFT fluid, which can lead to issues.
Are you referring to the temperature sensor in the radiator when you say compartment with a ATF in it?
 

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The radiator has an upper tank that holds several gallons of coolant and it also has a lower tank that holds a couple of quarts of ATF.

One big radiator that has two tanks.
How does it get in there if there are no transmission lines attached to the Passports radiator? According to the Honda diagram the only things are the upper and lower radiator hoses, the temperature sensor that activates the fans and some mounts for the fans.
I would love to see a cut away of what your saying.🤔
 

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We purchased the transmission cooler and then changed our minds and didn’t get it installed. We may decide later to re-purchase and have installed if we plan to tow anything near or above 3500 pounds. There are lots of posts on here by people who had them installed and were unhappy about the way the transmission shifted, or weird noises it made. That’s what prompted us to hold off on moving forward with it. Do a search to learn more about it before you decide whether to proceed.
 

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Don't do it!!! Honda has under engineered the transmission cooler that they sell for the Passport.

It will cause a grinding/buzzing noise every time that is shifts from 7th to 8th gear under light throttle! This also happens to be between 42mph -50mph which is mostly the speed you are at driving around town.

Most including myself believe it causes a pressure drop and causes the Dog clutch to drag. Honda will do NOTHING about it and tell you it is a normal characteristic of having the transmission cooler? Luckily I have an upstanding dealer so I requested that they take it off and give me my money back as it completely devalues my car and in no way is good for the transmission.

Cooler off noise gone!!!

Probably could be solved with a software update to increase line pressure across the board in Passports because Ridgeline's come from factory with cooler and no noise but, Honda won't give the Dealers anything to help!

This is truly false advertising as they advertise an SUV that will tow 5000lb when properly equipped with the transmission cooler but when you install the cooler it causes a serious issue with the transmission!!!
 

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Don't do it!!! Honda has under engineered the transmission cooler that they sell for the Passport.

It will cause a grinding/buzzing noise every time that is shifts from 7th to 8th gear under light throttle! This also happens to be between 42mph -50mph which is mostly the speed you are at driving around town.

Most including myself believe it causes a pressure drop and causes the Dog clutch to drag. Honda will do NOTHING about it and tell you it is a normal characteristic of having the transmission cooler? Luckily I have an upstanding dealer so I requested that they take it off and give me my money back as it completely devalues my car and in no way is good for the transmission.

Cooler off noise gone!!!

Probably could be solved with a software update to increase line pressure across the board in Passports because Ridgeline's come from factory with cooler and no noise but, Honda won't give the Dealers anything to help!

This is truly false advertising as they advertise an SUV that will tow 5000lb when properly equipped with the transmission cooler but when you install the cooler it causes a serious issue with the transmission!!!
Mine seems to work just fine :)

No Noise, No shifting issues and I tow 4800lbs.
 

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Hello all.

Looks like @drifter64 has firsthand experience about the transmission cooler.

I just purchased a 2023 Passport Elite AWD and added the 5k tow package with the trans cooler. Since the dealer has not installed it yet, I can still cancel the order.

It seems only one has reported issues with it on this thread, with three others saying no issues. Could @drifter64 have had an isolated issue that may/may not be related to the ATF cooler?
 

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Hello all.

Looks like @drifter64 has firsthand experience about the transmission cooler.

I just purchased a 2023 Passport Elite AWD and added the 5k tow package with the trans cooler. Since the dealer has not installed it yet, I can still cancel the order.

It seems only one has reported issues with it on this thread, with three others saying no issues. Could @drifter64 have had an isolated issue that may/may not be related to the ATF cooler?
If your going to be towing anything that would require a cooler to meet Honda's specs for the vehicle I would get it installed.

As for the user that has had issues and even others that have had issues.

I would say its isolated if it was not Honda would do something about it.
 

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If your going to be towing anything that would require a cooler to meet Honda's specs for the vehicle I would get it installed.

As for the user that has had issues and even others that have had issues.

I would say its isolated if it was not Honda would do something about it.
Not sure about the 2023's but it is a consistent issue with the 2019-2022's. You can find it in the forums here under transmission buzzing grinding noise after trans cooler. One guy also even has recordings!

You can manually make it happen if you have the cooler by putting it in sport mode, then go 42-50mph and paddle shift from 7th - 8th gear.
 

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If your going to be towing anything that would require a cooler to meet Honda's specs for the vehicle I would get it installed.
Not sure about the 2023's but it is a consistent issue with the 2019-2022's. You can find it in the forums here under transmission buzzing grinding noise after trans cooler. One guy also even has recordings!

You can manually make it happen if you have the cooler by putting it in sport mode, then go 42-50mph and paddle shift from 7th - 8th gear.
I will have to give it a try.

Thanks for the info!
 

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If your going to be towing anything that would require a cooler to meet Honda's specs for the vehicle I would get it installed.

As for the user that has had issues and even others that have had issues.

I would say its isolated if it was not Honda would do something about it.
Before I requested my money back I was doing some part number checking and did notice that the 2023's do indeed have a different number for the transmission cooler? Ridgeline's also have a different part number??
 

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Before I requested my money back I was doing some part number checking and did notice that the 2023's do indeed have a different number for the transmission cooler?
Trying to find out what year your PP is.

I just got a '23. If they changed the part number on the 2023+, we can hope the issue has been identified and rectified.
 

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Not sure about the 2023's but it is a consistent issue with the 2019-2022's. You can find it in the forums here under transmission buzzing grinding noise after trans cooler. One guy also even has recordings!

You can manually make it happen if you have the cooler by putting it in sport mode, then go 42-50mph and paddle shift from 7th - 8th gear.
Our '21 Elite with dealer installed cooler has no issues. Shifts great & none of the buzzing-grinding noise when shifting in any gears or driving at any speeds. This is our 3rd ZF transmission and the smoothest, best shifting one yet. That said, to suggest pulling 3,000 to 5,000 pound trailers without a tranny cooler is not good advice at all. Just my 2Cents worth...
 
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