Do I need a transmission cooler

0dyfamily · Jan 22, 2017

If you use a Long Tru-Cool LPD cooler, you won't need the thermostat, IMHO. We have a decent number of Odyclubbers who live in Canada and on the snowy parts of the U.S. eastern seaboard who have mounted an LPD cooler (mostly the 4544, but sometimes the 4543), and none of them has reported any problems with overcooling of the ATF during wintertime.

Just my take on the subject. For your light duty towing applications, the above coolers are more than enough, and not having the thermostat keeps it simple (and less prone to malfunction).

OF

anav_ds · Jan 22, 2017

Fair enough, so the decision is down to Tru-Cool LPD and replace the ATF cooler, or put it in line.
The total replacement concept may be overkill but avoids a potential bad outcome (mixing fluids) which has been described as rare 2007 and after (but note!!! I just had to replace the metal line of tranny coolant system that leads into the rad).

However Dave has suggested the ATF cooler is dual purposed, in that it helps warm up the Tranny when cold (or limit excessive initial cooling) and which begs a similar question can the Tru-cool also provides dual purpose and if not, what is the ramification? Tru-cool LPD has been described as self regulating and perhaps this serves enough purpose to cover off what the ATF cooler does??? From other sources........ the first levels of the LPD are basically a bypass section such that the cold viscous fluid flows more easily from the intake to the outtake (= less cooling effect) and when temperature increases the coolant is somehow diverted back to the main part of the device where flow is restricted and forced to cover more area to reach the outflow (=more cooling). I think what they have done is design the cooler as described AND moved what used to be an external bypass/redirect mechanism into the LPD device, and can only assume it has either an pressure or temperature component to control the redirection ????.

{Or possibly buy the cheaper Derale 13502 tranny cooler in line.}

Before the discussion gravitates to where in line if not replacing the ATF cooler entirely we need to dissect Dave's comments (mostly cause aka Schultz "I know nuthing") because I don't see how the ATF cooler helps warm up the Transmission when its cold - and I am assuming at startup?? I understand the radiators function via a thermostat not to cycle coolant to the Rad until the engine temperature rises. Am I to assume that the ATF also has a thermostat and bypasses the Rad Portion (the ATF entirely or extremely reduced flow) until the Transmission coolant rises to a certain temp?? Hopefully Dave can shed some light here!

If this is indeed the case, then it would make sense to put any additional cooling capacity at the back end, as liquid is going from the end of the ATF loop coming out of the RAD to the transmission area. This normally seems to be a section of rubber hose ( cut hose splice in line for auxiliary cooler). In this way, the ATF coolant would not enter the RAD area and thus NOR enter the auxiliary coolant loop as they are both bypassed at the ATF thermostat (if one exists).

Please advise.

0dyfamily · Jan 22, 2017

1.) I've never heard of the radiator in-tank ATF cooler malfunctioning in the Odyssey. The hose barbs and in-tanker cooler are made of brass (I removed one from a Honda Accord radiator). That metal line, IIRC, is between a pair of flexible lines on the ATF-return-to-transmission line. If you a truly concerned, remove the radiator in-tank ATF cooler from the cooling loop...but if there is no visible damage from corrosion to the hose barbs sticking out of the bottom tank of the radiator, and you've kept up on coolant servicing, I wouldn't take it out of the loop.

2.) The radiator in-tank ATF cooler is a heat exchanger. It does help the ATF warm up more quickly, since the coolant will warm more rapidly than ATF. Tru-Cool markets their LPD coolers as having top plates with very low restriction that allow more viscous ATF to pass through. As the ATF heats up, it has an opportunity for more of it to travel through the plates in the main body of the cooler. I like the Tru-Cool products.

3.) Most ATF cooler manufacturers recommend this ATF "cooling loop": [ATF from transmission] ---> [Radiator in-tank ATF cooler] ---> [ATF cooler*] ---> [ATF return to transmission]. That's how my Accord and two Odysseys are set up.

The [ATF cooler*] can be Long, Derale, B&M, Haynes, or other name brand, etc.

OF

davedrivesody · Jan 22, 2017

anav_ds said:
Am I to assume that the ATF also has a thermostat and bypasses the Rad Portion (the ATF entirely or extremely reduced flow) until the Transmission coolant rises to a certain temp??

AFAIK, the transmission has no thermostatic control on the ATF cooler circuit.

The ATF warms up from cold start in two ways:
1. The PCM delays torque converter lockup so the TC generates more heat.
2. The ATF picks up heat from the radiator cooler (i.e. heat exchanger).

Dave

anav_ds · Jan 23, 2017

Thanks for the feedback. I will go with the tru-cool 4454, and I found a local place I can pick one up for $75 plus tax!

anav_ds · Jan 23, 2017

Hi Dave, thanks for that info.
Number 1. I don't understand, so need more laymans details. What does the PCM?? or TC?? have to do with the ATF and ATF cooler portion within the rad?
Number 2. Count me the uneducated but logical sceptical because the rad flow is basically off at startup until the thermostat determines the water circulating around the engine is warm enough such that cooling can now be applied. Thus, the radiator initially is not going to provide heat exchange possibilities with the ATF.

davedrivesody · Jan 23, 2017

anav_ds said:
What does the PCM?? or TC?? have to do with the ATF and ATF cooler portion within the rad?

The PCM (Powertrain Control Module) is the computer that controls engine and transmission functions. The ATF temperature sensor tells the PCM when the ATF is cold. The PCM then delays the lockup of the torque converter to generate more heat in the ATF.

The TC (Torque Converter) is the part of the drivetrain that transfers engine torque to the transmission. It is the biggest source of heat for the ATF, at least when not locked up. So keeping the TC unlocked generates heat to warm up the ATF quicker.

anav_ds said:
Count me the uneducated but logical sceptical because the rad flow is basically off at startup until the thermostat determines the water circulating around the engine is warm enough such that cooling can now be applied. Thus, the radiator initially is not going to provide heat exchange possibilities with the ATF.

You are correct, the radiator will have no heat immediately after startup. However, it will have heat after driving for a while, long before the ATF has warmed up. So at that time, when the coolant is warmer than the ATF, the ATF will absorb heat from the coolant.

Dave

anav_ds · Jan 23, 2017

Okay, that leads to more questions (of course). So the Torque convertors function is wholly dependent upon the ATF?? Seem strange to me. When may I ask can the Torque Converter primary function be delayed? I interpret that as stating, the van will not move until the ATF is warm enough???

I get the radiator bit then that makes sense. So ATF flow is not regulated per se. It circulates period (oops Sean Spicer talk). The important question is -Where is the ATF temperature sensor physically located? For example, if I was to bypass the ATF loop, it would be best to do it after the Temp Sensor and before the ATF cooler section and in that regard, the PCM would still provide the functionality desired wrt TC. I would be hooped if the temp sensor was on the return to the transmission side of the radiator.

Im assuming that the PCM turns off delaying lockup in winter when RADIATOR heating is occurring and that is an important element of the ATF loop. If I dont bypass the ATF cooler in the RAD, and this section of pipe fails and my tranny blows up, Im sure DrDave and DrOdy will pay for it ;-))). Seriously, if the tru-cooler has a low temp bypass and clear non- obtructive path to more viscous ATF, will that alleviate concerns? Wouldnt the ATF eventually get heated? Perhaps with more info on the value of, functionality, flexibility of performance of the PCM-TC, I could better understand the ramifications of doing a bypass. For example, if using the tru-cool in a bypass, the ATF sensor will show that the ATF remains cooler longer at startup due to NO RAD heating influences. Thus the PCM will tell the TC to delay lockup longer. Good? Bad? Ugly?? How will the ATF ever warmup without the rad heat exchange?

John Clark · Jan 23, 2017

anav_ds said:
Okay, that leads to more questions (of course). So the Torque convertors function is wholly dependent upon the ATF?? Seem strange to me. When may I ask can the Torque Converter primary function be delayed? I interpret that as stating, the van will not move until the ATF is warm enough???

It only delays lock up (at cruising speeds) until the ATF reaches a temperature threshold. The TC will still do its job, just not in lock up. The TC's job is to slip at idle and then starts to grab at higher RPM. In older vehicles the TC's never locked up and slipped all the time. Now there is lock up which feels like another shift (some mistakenly call it overdrive) which increases fuel economy and saves wear on the TC at cruising speeds.

davedrivesody · Jan 23, 2017

anav_ds said:
Where is the ATF temperature sensor physically located?

Not sure if it's in the ATF flow to the cooler or from the cooler. My best uneducated guess is the former, in the ATF flow to the cooler. That location would indicate the ATF temperature more accurately.

The sensor is mounted in the transmission case. You have no control over its placement in an auxiliary ATF cooler installation.

anav_ds said:
How will the ATF ever warmup without the rad heat exchange?

The radiator heater only speeds up the warming of the ATF after a cold start. Without the radiator heater, the ATF will definitely warm up, just a little slower. An unlocked torque converter generates a lot of heat (hence the need for an auxiliary cooler) and also engagement of the clutches generates heat.

anav_ds said:
if using the tru-cool in a bypass, the ATF sensor will show that the ATF remains cooler longer at startup due to NO RAD heating influences. Thus the PCM will tell the TC to delay lockup longer. Good? Bad? Ugly?

The engine will burn more fuel. There will be more wear on the torque converter, and on the mechanical parts of the transmission generally. Cold ATF lubricates less well than ATF at operating temperature. (Ideal ATF operating temperature is 180F.)

Dave

manualman · Jan 23, 2017

I'm WAY late to the party, but that popup in the OP post don't weigh 1,500# when it goes camping. MAYBE it weighed 1,500# bone dry and empty on the assembly line before the AC, furnace, awning, LP tank(s), battery, fridge, water heater (if equipped) were added. Loaded to go camping that baby weighs 2,200-2,700#. Betcha.

anav_ds · Jan 23, 2017

Thanks much Dave and John. Okay so weighing the pros and cons.........
BYPASS: Removes risk of mixing antifreeze and ATF $7500 or more.
BYPASS: More wear and tear on TC and rest of transmission by ?? percentage? ***
BYPASS: Does not overly cool initially until ATF warms up (viscous coupling and bypass mechanism internally)

*** None of the transmission repair guys I have talked to sees any issues with BYPASS and have not mentioned the wear and tear noted here and perhaps they dont know any better?Why is it that they are not worried about the torque converter?? How much does it cost to repair?

So the question becomes how do I quantify the extra wear and tear on the bypass option. Put in another way, how significant is the heat exchange from the rad on initial startup. Assuming the MAIN role of the ATF loop in the rad is to COOL the ATF fluid in summer. (yes, no)?

No doubt the tru-cool in line would be of great benefit. The question now is for the bypass scenario; is the additional wear and tear, thus far not quantified or noted by transmission repair shops, too great of a negative factor and thus over rides the peace of mind of a potential tranny fluid contamination. If indeed the ATF bits inside the radiator are all brass should that alleviate my concerns, OR are there attachments/connector points that are still vulnerable (how does aluminum react to chemicals (road salts, antifreeze etc......)...

How does one find out about the bits and pieces of the ATF cooler. Are there documents schematics anything that can be found???

Basically the install is going to be straight labour costs for the most part, taking apart the front end of the honda its going to probably be a two hour job (84x2=168 plus tax) (one hour if I am lucky, 3 hours if unlucky). The question becomes do I want the stock install with the provided tie clips etc......... or do I want a different perhaps better job done ie mounted to the frame perhaps.

IN other words do I want the cooler to be physically touching the rad or separated. I think the kits have little rubber pads to separate but it would still be hanging off the rad. I like the idea of physical separation and avoiding any chance of metal on metal or friction rubbing.

John Clark · Jan 24, 2017

I think you're way overthinking all this.

I prefer the cooler mounted on its own. I didn't use the tie straps on mine.

anav_ds · Jan 24, 2017

I would agree but its in my nature to do so before I make a decision. It ensures the least amount of unintended consequences for those decisions!.

davedrivesody · Jan 24, 2017

anav_ds said:
how do I quantify the extra wear and tear on the bypass option.

Too many unknown variables to estimate a wear factor (ambient temperature, driving style, length of average trip, etc.). You may be able to read the ATF temperature through the OBD port and then to measure the time needed to warm up the ATF.

anav_ds said:
Assuming the MAIN role of the ATF loop in the rad is to COOL the ATF fluid in summer. (yes, no)?

That would be true.

anav_ds said:
do I want the cooler to be physically touching the rad or separated.

I'm with John on this one. The cooler should support itself and have no contact with the radiator. The radiator was not designed to have anything piggybacked onto it. The weight and vibration of the cooler could damage the radiator.

Dave

vivankata · Jan 24, 2017

In my opinion the ATF cooler in the radiator can not heat atf when is cold.I would bypass it.This winter I had to empty engine coolant from my radiator when the car was at normal operating temperature. The top of the rad was hot but the bottom where the atf cooler is was so cold that I could work with my hands. The best way to warm ATF is to keep in gear so the TC can generate heat while sliping. Here is a helpful link for your choice:
CoolerRecap

manualman · Jan 24, 2017

If it helps you make a decision, my 2003 Ody is still tooling about (for others now) on its original transmission, having towed at least 20,000 miles a 2,700# trailer plus our family of 5 aboard. It has a plain tube and fin hard mounted in series with the radiator cooler. No fancy thermostat. It has 223,000 miles on it. Worry less about the cooler specs and spend that energy assuring timely ATF fluid changes over its life.

surgeon · Jan 24, 2017

I also with John Clark and davedrivesody on this. My the way this thread is going I am assuming that you have not really read the other one or two major threads on the cooler (no offense intended). Of course few minor questions are different in this thread, which would have served a good reference there as well. Install is very simple, either strapped to radiator (oldskewl did that if I can recall) or mounted to frame. If you see the thread there are plenty of pics and install was extremely simple. When I did mine, I did not drill any special holes or anything. Used default holes or bolt points.

http://www.odyclub.com/forums/27-di...ums/27-diy-modifications/7617-aftermarket-atf-cooler-installation-notes-39.html

Much work and discussion is in that thread.

jnissen · Jan 25, 2017

I put one in after adding my hitch. I typically haul a small utility trailer in the neighborhood for a lawn mower so i was in no hurry to do the job. I don't know why I waited since the job actually was not all that difficult. Took me a couple hours and have been enjoying lower temps ever since. I have since hauled dual axle trailers and a fair amount of weight taking kids to college and setting up a home out of state. Overall zero problems but I only have 148K miles.

BTW - Firm believer in the 3X drain and fill every 35K miles.

macdon9876 · Sep 1, 2017

Sorry to resurrect this thread from the dead, but my question is along a similar theme.

I'm driving a 2016 Odyssey in Nova Scotia, Canada. We are campers and we are finally planning to buy a popup trailer this fall or next spring.

We already have an aftermarket hitch, used for a bike rack to this point. The dealer will gladly install the OEM tranny cooler for $622 plus tax - gee, thanks!

I called around to a few local transmission shops, and they all had the same question: how heavy is the trailer, and how far will I be driving. Two of the three questioned whether I even needed an ATF cooler, especially if the trailer isn't too heavy and/or we don't plan on towing it across the country.

A mechanic at one shop suggested that, for the 98% of driving I'll do without towing, an ATF cooler can actually OVER-cool the fluid (especially in the winter), which can cause its own problems. His advice was to buy a scan tool to monitor the ATF temperature, pull over if/when it went over 225F to let the fluid cool down, and carry on after the stop. Seems like an odd suggestion but he was also talking himself out of a sale.

(As an aside: exploring this forum seems to suggest that the scan tools may or may not give reliable ATF temperature readings, so that is a separate issue! I e-mailed ScanGauge and they gave me a code that supposedly works for 2016 Odysseys, if I decide to go that route.)

Then there is the warranty issue with four years left on the Power Train coverage. We're also concerned with the longevity of the van as we'd like to keep it for a number of years - it's a great vehicle!

Anyway, any thoughts out there would be appreciated, especially those who tow in colder climates. Nova Scotia has a freeze-thaw type of climate, not a deep freeze for three months like some places.

Do I need a transmission cooler

0dyfamily

anav_ds

0dyfamily

davedrivesody

anav_ds

anav_ds

davedrivesody

anav_ds

John Clark

davedrivesody

manualman

anav_ds

John Clark

anav_ds

davedrivesody

vivankata

manualman

surgeon

jnissen

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