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Discussion Starter #1
In looking through the Forum, may I assume that SMOD is a 1G problem and has since been rectified in the 2G?

Bill
 

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It's from the Transmission oil mixing with the Radiator fluid due to the connection for transmission cooling failing.

Strawberry Mixture Of Death as it's called as SMOD. And no the RL2 has a different radiator setup. Not happening on it.

Steve
 

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What is SMOD?
I believe SMOD refers to strawberry milkshake of death, which is not some Frankenstein creation found at your local Shake Shack or Steak and Shake but rather a Transmission killing condition that鈥檚 occurs when the transmission cooler that is often located in the radiator for the engine fails and leaks ATF into the coolant. This causes a pink translucent fluid that is very close in resemblance to a melted pink milkshake. This mixture is detrimental to a transmission and almost always results in failure. Also on the second gen the ATF cooler is a separate entity meaning if it were to break and leak it鈥檚 not going to end up mixed with the antifreeze from the engine.
 

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Discussion Starter #5
Yep, that is what I was making reference to with SMOD, so on one hand it is reassuring that that situation has been apparently rectified with the G2. Otherwise though, is it true that the G2 Ridgelines now do not have any transmission cooler other than that lil external jobbie tucked down at the bottom of AWD radiators, really? Maybe I am being pessimistic, for I am having problems thinking that would be enough, but I am foreseeing a replacement larger cooler for the OEM in the future of our Ridgeline, thoughts?

Bill
 

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Just to clarify, the SMOD is because of the design of the ATF Pre-warmer. NOT the ATF cooler behind the grill.

That said, Yes the G2 has an ATF cooler (25500-5J8-013) behind the grill. The G2 also has a Pre Warmer, but it is not integrated into the bottom of the radiator, but is on the transmission and has coolant hoses going to it. part number 25560-5B7-A01. Essentially a cube looking finned box made out of aluminum with 4 ports sticking out. Two for coolant and two for ATF.

I had a talk about this a month or so back as a possible alternative to folks with G1 and to use this to prevent SMOD.

What is SMOD?
Bro...... you got lots to learn lol
 

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G1 had an External ATF Cooler, It's related to the ATF Pre-Heating designed into the bottom of the Radiator, common across all Manufacturers.
396645


Quick look at the Radiator in the sketch from an online Honda Dealer, I don't see any hoses/fittings on the bottom of the tank Part Number: 19010-5J6-A01, I'll do some more digging.

Here are most of the (G1/1G) related Radiator and Transmission threads if you haven't found them all.

Happy Reading & Good luck

Radiator Failure @ Cooler Lines

Best Radiator Replacement

Pictures of Corroded/Rusted Radiator Fittings

Radiator Fail on 2006

UOA on ATF

Anatomy of OEM Denso Radiator

Poll(Never Posted) on Radiator/Trans Cooler Solution

Recent Radiator/Transmission SMOD!!!

Radiator comparison: Denso/Spectra/OSC

Catastrophic transmission/radiator fitting failure

Just turned 200000 miles and oh no,....
 

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Why criticize for asking the definition of an acronym that is not commonly discussed on the G2 Forum?
Was merely poking fun; not meant to be a snide comment or belittle you. It came from a place, where I presumed as you were from Jersey, that somehow it was a brotherhood. I apologize if it appeared offensive.
 

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Discussion Starter #10
OK, It appears to be my misunderstanding that there was a warmer/cooler integrated into the radiator which was the culprit for the SMOD and the outside cooler was an auxiliary cooler to this?

Bill
 

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OK, It appears to be my misunderstanding that there was a warmer/cooler integrated into the radiator which was the culprit for the SMOD and the outside cooler was an auxiliary cooler to this?

Bill
That's how it works on the G1, minimal research and I don't think the G2 will suffer the same issues
 

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OK, It appears to be my misunderstanding that there was a warmer/cooler integrated into the radiator which was the culprit for the SMOD and the outside cooler was an auxiliary cooler to this?

Bill
the heat exchanger on the bottom of the radiator is a pre-warmer, not a cooler. Though, even Honda, labels their part number for certain types as coolers. It is crazy.

Since the coolant reaches operating temps faster than oil, in this case ATF, the prewarmer on the bottom of the radiator served to bring the ATF to optimal operating temperature range quickly during the colder temps. The ATF cooler outside served as the 'cooler' where the warm ATF out of the transmission flowed through, cooled down and then entered the pre-warmer to reach operating temp. This prevented over cooling of the ATF fluid.

Not just the G1, but basically every other manufacturer out there had something similar to warm the ATF. Now everyone is switching to the sandwich type. Some ATF pre-warmers are bolted onto the transmission with internal ATF routing and only two ports on top for coolant. This is a design on the 9spd and 10spd Honda transmissions.

G2 is safe for now, unless the sandwich style fails somehow. @zroger73 mentioned that there was some issue with such sandwich units, but my memory is vague on that.
 

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Discussion Starter #14
So, just making sure that I understand correctly, with the 2019 transmission, warming/cooling lines do run through the radiator first, and then the exterior cooler, then back to the tranny, correct?

Just an interesting lil side note where I am somewhat taken aback at the cost of a new radiator for the Ridgeline, just a lil over $100 on HondaPartsNow, really? I just paid nearly three times that much for a radiator for our 1972 Chevy pickup!

Bill
 

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In the G2, there no heat exchanger in the radiator so lines go through the radiator.

The order is as below.
  • transmission to the ATF cooler
  • cooler to the prewarmer
  • prewarmer back to transmission.
 

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... The order is as below.
  • transmission to the ATF cooler
  • cooler to the prewarmer
  • prewarmer back to transmission.
I hope that pre-warmer only operates when needed. With the reports of the 6AT overheating when worked hard at slow sustained speeds, maximum cooling is needed not pre-heating. It sounds like the ATF fluid does not have a choice, it will be heated up even if it's burning up.
 

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Discussion Starter #17
In the G2, there no heat exchanger in the radiator so lines go through the radiator.

The order is as below.
  • transmission to the ATF cooler
  • cooler to the prewarmer
  • prewarmer back to transmission.
Do I assume that you meant to say, "In the G2, there (is) no heat exchanger in the radiator so (no) lines go through the radiator?
Where is this prewarmer located and how does it function?
Thanks,
Bill
 

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Do I assume that you meant to say, "In the G2, there (is) no heat exchanger in the radiator so (no) lines go through the radiator?
Where is this prewarmer located and how does it function?
Thanks,
Bill
Correct. G2 does NOT have a radiator integrated ATF pre-warmer. So NO ATF lines go to the radiator.
Instead, the ATF lines go to a sandwich-style heat exchanger (25560-5b7-a01, image below).
This heat exchanger has 4 ports on top: two for ATF and two for Coolant. The warm coolant enters the heat exchanger and warms up the ATF. This heat exchanger is bolted directly on top of the transmission housing (see image below, circled in blue). Such a pre-warmer is also present in other vehicle manufacturers (Hyundai for example).


<< Click to Enlarge >>

396857
396856


The ZF sourced 9-spd and the Honda 10-spd also have similar ATF pre-warmer. However, they only have two ports on top for the coolant. The heat exchanger has internal ATF ports that circulate ATF through them and are also bolted to the transmission housing. With the 9-spd slated to be installed in the G2 Ridgeline, one can expect the design to carry over.
 

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I hope that pre-warmer only operates when needed. With the reports of the 6AT overheating when worked hard at slow sustained speeds, maximum cooling is needed not pre-heating. It sounds like the ATF fluid does not have a choice, it will be heated up even if it's burning up.
Note that if the fluid is warmer than the coolant going into this 鈥減re-warmer鈥, the coolant (even though 鈥渉ot鈥) will still help to cool the hotter ATF. Based on virtually all manufacturers using this design, I am going to guess that coolant temperature is close to ideal ATF temperature so this device acts as a buffer to warm it up faster but doesn鈥檛 make it too hot either.

I too though have to wonder how long this new type of heat exchanger will last before causing SMOD.
 

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Correct. G2 does NOT have a radiator integrated ATF pre-warmer. So NO ATF lines go to the radiator.
Instead, the ATF lines go to a sandwich-style heat exchanger (25560-5b7-a01, image below).
This heat exchanger has 4 ports on top: two for ATF and two for Coolant. The warm coolant enters the heat exchanger and warms up the ATF. This heat exchanger is bolted directly on top of the transmission housing (see image below, circled in blue). Such a pre-warmer is also present in other vehicle manufacturers (Hyundai for example).
View attachment 396857 View attachment 396856

The ZF sourced 9-spd and the Honda 10-spd also have similar ATF pre-warmer. However, they only have two ports on top for the coolant. The heat exchanger has internal ATF ports that circulate ATF through them and are also bolted to the transmission housing. With the 9-spd slated to be installed in the G2 Ridgeline, one can expect the design to carry over.
Very cool (all puns intended)! It looks like Honda learned some lessons with the Denso radiators they used in the Gen1 and did not want to repeat their SMOD mistake again.
 
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