Hi Ski,

I didn't monitor my temperatures before installing the cooler, but this is the one I installed back in April:

https://www.etrailer.com/Transmission-Coolers/Derale/D13503.html

With the cooler I seem to run 80-100 degrees above ambient, which can be an issue in cold weather. The couple times I monitored last winter I was only getting to 100-110 degrees, which can be detrimental because it doesn't get hot enough to drive out moisture accumulation.

I haven't seen any official Honda spec, and the factory shop manual is silent about temps. But Ford transmissions dating back to the mid-'90s were rated up to 230* for continuous operation, and up to 250* for 1/2 hour at a time. You could run those transmissions at 225* every minute of operation, and according to the engineers you would never see decreased life. Modern Ford transmissions have a thermostat, and the latest generations have that set to 195*. I'd be downright shocked if a modern Honda transmission was less tolerant, as fluid technology has improved substantially over the last 20 years. I wouldn't bother with an external cooler if you drive in cold weather. Kentucky is warmer than we are, but I wouldn't install an external unless I was towing something.

Why would you want to switch to MaxLife fluid? It's a multi-vehicle formula that meets a lot of older specifications, but I haven't seen anything from Valvoline or anyone else suggesting MaxLife is a suitable replacement for DW-1. You think stepping back ten years in fluid technology is going to make your brand-new transmission last longer? Lots of folks have had good luck on Hondas with MaxLife, and I'm not trying to minimize that. But most of those had transmissions that called for Z1 fluid, and the 6-speed transmission certainly does not. You may kill your transmission long before its time by switching to an unapproved transmission that doesn't meet the right specs.

 

Hi Ski,

I didn't monitor my temperatures before installing the cooler, but this is the one I installed back in April:

https://www.etrailer.com/Transmission-Coolers/Derale/D13503.html

With the cooler I seem to run 80-100 degrees above ambient, which can be an issue in cold weather. The couple times I monitored last winter I was only getting to 100-110 degrees, which can be detrimental because it doesn't get hot enough to drive out moisture accumulation.

I haven't seen any official Honda spec, and the factory shop manual is silent about temps. But Ford transmissions dating back to the mid-'90s were rated up to 230* for continuous operation, and up to 250* for 1/2 hour at a time. You could run those transmissions at 225* every minute of operation, and according to the engineers you would never see decreased life. Modern Ford transmissions have a thermostat, and the latest generations have that set to 195*. I'd be downright shocked if a modern Honda transmission was less tolerant, as fluid technology has improved substantially over the last 20 years. I wouldn't bother with an external cooler if you drive in cold weather. Kentucky is warmer than we are, but I wouldn't install an external unless I was towing something.

Why would you want to switch to MaxLife fluid? It's a multi-vehicle formula that meets a lot of older specifications, but I haven't seen anything from Valvoline or anyone else suggesting MaxLife is a suitable replacement for DW-1. You think stepping back ten years in fluid technology is going to make your brand-new transmission last longer? Lots of folks have had good luck on Hondas with MaxLife, and I'm not trying to minimize that. But most of those had transmissions that called for Z1 fluid, and the 6-speed transmission certainly does not. You may kill your transmission long before its time by switching to an unapproved transmission that doesn't meet the right specs.

Tom,
A lot of great information to digest. Does that Derale have a 'Bypass'? That would definitely help in the cooler temps. From what I gather the TrueCool does.

Ski

 

Ski, one of the guys on the BITOG (Bob Is The Oil Guy) forums got in contact with Ashland Chemical not too long after Honda ATF DW-1 hit the shelves, and their Valvoline MaxLife supports the DW-1 spec, so he said.

I cannot recall the thread or BITOG forum member, but I do remember that information, but it's old info from probably 2011 or thereabouts. TomB985 is right in that currently the MaxLife bottle doesn't list DW-1 on the label. Makes me want to email Valvoline (or Ashland) and see if MaxLife still does support the Honda DW-1 spec.

Curiously, one of our Odyclub forum members noted sometime last year that Valvoline did change some of the MaxLife ATF viscosity numbers very slightly. Chemistry changes? I don't know, but if Ashland is like other larger chemical concerns producing lube and hydraulic fluids, they are always working to improve their offerings and stay abeam what customers need with newer vehicles.

The current stock Honda ATF cooler is pretty small, but even then this latest one is the best Honda has put out to date.

The hottest I've seen using Honda stock ATF cooling is 250-deg F at the cooling loop outlet, and 200-deg F "cooled" ATF back to the transmission on my datalogger. Ambient temp was mid-70's-deg F while climbing up California's Cajon Pass, driving very carefully in the slow lane, and I wasn't even towing anything.

After that toasty ATF experience (and an ATF change) I ditched the Honda ATF cooler and installed a Tru-Cool ATF cooler. Like TomB895 did, I went with something larger than the pretty small Honda OEM ATF cooler. My choice was a monster Tru-Cool Max 4739 ATF cooler with a custom MOCAL OT1 thermostatic control. My ATF temps get to about 140-deg F, and stay there. Really, after much installation pain, in hindsight nobody needs a Godzilla-size ATF cooler for a minivan.

We have had a number of eastern seaboard Odyclubbers use the Tru-Cool 4544 LPD cooler with really good success, even during some pretty chilly Atlantic winters. No thermostatic controls needed. It sure seems to be right-sized for our Odysseys. Great price, not a difficult installation, just big enough. It's a win to the third power.

Our own bbylon5 had an exchange of information with Road & Track magazine's Tech Correspondence people, and yes, keeping ATF below 180-deg F was something they recommended, IIRC. bbylon5 fitted an Earl's ATF cooler and a thermostatic control plus a Magnefine inline filter. Earl's and MOCAL coolers are the platinum standard.

By the way, Tom's Derale cooler is pretty bomb-proof, too. When I was much younger, it seemed every off-road racer at So Cal's Saddleback park had a Derale cooling setup of some sort; popular because of their durability, and they work really well.

I can't compare my datalogger ATF numbers to ATF temp numbers generated by the PCM, as our two older Odys use ISO protocols and there is no ScanGauge PID for ATF temp (all Odys through 2006). In 2007 Honda adopted CAN protocol to comply with newer OBD II requirements, and this does allow an ATF temp data feed to be drawn from the PCM via a ScanGauge. I haven't heard of anybody instrumenting their ATF cooler lines on a newer Odyssey to see how actual numbers from a datalogger compare to the PCM ATF Temp data feed to a ScanGauge.

OF

P.S. Sorry about the length of the reply.

 

Odyfamily,

No worries on the post length.....great read! I may email Valvoline and/or Ashland as well to check on ML's comparison with DW-1's specs if I can find the time. Yes I was looking at the TrueCool 4544 LPD Cooler as so many in the forum have had great success with it over the years. Don't see the need for a thermostatic control but I do like the idea of the Magnefune inline filter for ease.
Thank you for the temp. specs that's what I was looking for and is pretty inline with what I was familiar with. Keep all that 'knowledgeable info' coming!

Regards,
Ski

 

Mark Kovalsky is right. Essentially, most hydraulic fluids used in automatic transmissions, tractor output drives, simple constant speed drives, and so forth, all benefit from having the fluid temp warmed up to between 5-deg F to 15-deg C (41-deg F to 59-deg F) at a minimum to approach the "knee in the curve" and thus begin to realize substantial and measureable efficiency benefits as temp increases.

Here's an example with some different standardized grades of hydraulic fluid. Graph measures hydromechanical losses as a function of temperature, ISO Grade and VI (viscosity index):

Note that the gain in freedom from hydromechanical losses hits an asymptote as we approach 40-deg C (104-deg F). In short, it doesn't take much total temperature to get there. Once above 40-deg C, efficiency gains measured against temp increase are incrementally much smaller.

Essentially, once above 40-deg C, in general any further increase in hydraulic fluid temp for these generic hydraulic fluids doesn't net huge gains in efficiency. True that...to get into the "sweet spot" between volumetric efficiency (ability to pump the fluid) and not have your power transmission equipment lose a lot of input power to fluid circuit losses, you have to get the fluid warmed up. My thermostatic controls on our vans are fully open at 140-deg F, so that is one significant contributing factor to pretty good MPG on my old vans despite their advanced age. I like staying below 180-deg F, but I think the next time I install one of these ATF cooling setups on a newer vehicle (whatever I buy in the future), I'll probably use a Mishimoto inline thermostat with their 71-deg C (160-deg F) thermostat.

Automotive ATF's generally fall between 100 and 200 as far as the viscosity indexes go (the higher the number, the more "stable" the measured viscosity is against temperature change), so the above chart is a good starting point for understanding Mr. Kovalsky's spot-on assertion that very cold ATF temp squanders efficiency.

This is why I like the Tru-Cool LPD ATF coolers, and wish I'd installed one. They have the restriction-free plates that allow the bulk of cool ATF to flow without exchanging much heat, but once viscosity drops with increasing temperature, more ATF flow is evident within the rest of the cooler's bulk. This eliminates the need for a thermostat when using a properly sized cooler, according to the people at Long who make the Tru-Cool lineup.

On that note, I was climbing up a mountain highway one calm, sub-freezing morning into Wolf Creek in Colorado. I was driving carefully, and even with the stock Honda OEM ATF cooler, my datalogger was showing ATF outlet temp exceeding 200-deg F on our 2002 EX as we made it to our ski resort destination. The alarmingly hot Cajon Pass was on a later trip. Those experiences drove me to augment the ATF cooling loop with more robust equipment.

All Honda trannies are pretty small relative to what they're asked to do. The portion aside from the torque converter containing gearing and clutches and sump is about the size of a large gym duffel, even on the newest one. They warm up their ATF quickly when asked to transmit a lot of power. The van has always weighed in at about 2.2 tons since 1999.

OF

P.S. Man, I just cannot word this any better and in a more concise fashion.

 

Thanks OF, can't really disagree with any of that. I'd add that temperatures above 160 are important to drive moisture out of the fluid.

The transmission in my '15 F150 has a thermostat from the factory and a relatively large cooler in front of the radiator. It's rated to pull 10,700 lbs, so it's a bit of a different animal from the Odyssey. Anyway, it has a digital transmission fluid temperature gauge built into the LCD information display, and I was keeping an eye on temperatures today. My average temp once warmed up was 199 degrees, and it peaked at 208. The transmission lives at this temperature, and this transmission design has always had a thermostat regulating to this temperature. It's been in use since 2006, and failures are downright rare. I know, it's not a Honda, but I think it well illustrates the fact that you can't apply old-fashioned logic to modern transmissions.

If the factory cooling was inadequate we'd be seeing far more failures than we see. I've been on OdyClub for about a year, and I've not heard of a 4th gen van with a failing transmission, and we have some users with over 150,000 miles on their vans. A couple of peeks into the previous-gen forum didn't reveal any either, but of course I'm sure some have happened. I don't think cooling is a problem for these vans, and I don't think you're going to gain anything by messing with the factory system or fluid unless you see some special operating conditions.

 

Tom, a truck tranny utilizing planetary gearsets sure is a different beast, true, true. Ultra reliable. Ultra strong. Ultra reliable. If Borg-Warner didn't hold so many patents on this ultra reliable architecture (did I mention reliable?), Honda would not have been driven to make the first Hondamatic tranny. Many small vehicle manufacturers do the same, building automatic trannies that are essentially manual transmissions with a clutch package for each driven gear.

As well, you don't hear about late-2004 5-speed trannies going south. People who own these gems do not sell them. Essentially, pushed by the NHTSA, Honda fixed the 3rd clutch ATF flow problems that caused the entire mess from 2002-early 2004.

Thanks OF, can't really disagree with any of that. I'd add that temperatures above 160 are important to drive moisture out of the fluid. ...

Yes! If the amount of water in the ATF exceeds the hold-up capability of the dispersants in the ATF additives package, you end up with small micelles of water resident in the ATF where unfavorable chemical reactions can occur, and we're not talking just simple rust. In total, these accelerate the demise of a favorable TBN (total base number) to values that drive us to change the ATF.

In short, water is bad. My setup rarely gets to 160-deg F, so I know condensation can rear it's ugly head. That's why I do a periodic ATF drain and refill on all of our cars & vans, every other oil change. That all-important ATF additives package resident in what might otherwise be just plain old raw hydraulic fluid has the whole shebang of dispersant agents, compounds that hold small particulates in solution, items geared toward preserving TBN, anti-foaming agents, clutch friction modifier compounds, bearing friction modifier compounds, ad infinitum. Refreshing it once in a while with a periodic drain/refill is a good idea. Removing entrained water is a great idea, for sure.

Funny thing is, I learned about these things from a very good article on synthetic lubricants penned by a journalist who interviewed several chemists, and published this good read in a bass fishing magazine. Now that's a really strange "meeting of the minds."

OF

 

I've seen a few makers gravitate towards the "make a manual trans into an automatic" pathway, but I think Honda is the only one to make it really, really work.

The big design feature Honda uses is when there is a gear change, as one gear is disengaging, the next gear is engaging, and there is a brief moment when both clutch packs are simultaneously partially engaged (both briefly slipping, lightly at that, by design) so that you don't get a jolting shift. The best analogy to this is that this brief dual engagement of clutch packs performs the same duties as a synchro in a manual trans. Does it generate heat when doing a lot of shifts in city driving? Most likely. However, they've perfected the science, in my small opinion.

Earlier in another thread, I'd called it a "weak" design in the upper gears. I guess I have to qualify that I'm in a pretty narrow spectrum of people who want access to all gears while towing heavy, even where the torque curve picks up at the lowest possible RPM in the highest gear. That's probably not a wise use for any non-truck transmission, and as another poster noted, if I'm doing that, I'm not using the right tool for the job. It might be time to buy a truck...but I'm intent on keeping my 13-year-old Odyssey. 162,000 miles of mostly hard city miles, and I'll probably drive it into the ground.

The current tranny is the best ever, because it was made for the gross weight and horsepower class the current Ody lives in. I still don't like the idea of no access to 5th gear manual selection, but I guess I'll just have to suck it up. Is it good? Well, it easily meets market demands for reliability, efficiency, and usefulness for the owners, which equals good sales and happy customers. Honda isn't about to change a successful formula for just one guy on a minivan forum whining about using all of the gears (oh, that would be me).

Just got a good look at a friend's 2015 TE, and man, it's the best thing going in style and usefulness and power and handling and reliability. I can't find anything better, hands down....this fella wants one.

OF

 

120-160 degrees using no cooler and Amsoil ATF (outside air temps 70-80. Most days I dont see over 140. Im assuming due to the far superiority of the amsoil product it just runs cooler. I did purchase a ultragauge to monitor and a oem cooler which is yet to be installed along with 7 pin and brake controller to tow my RV. 2015 oddy exl. Once I get the cooler on ill let you know

 

What were your temps before the fluid change? What's your driving style? It can take over 30 minutes for the transmission to come all the way up to temp, how long are you driving when you're pulling these numbers?

Just looking for more info. I've never heard of substantially cooler temperatures from switching fluids. Not saying it isn't possible, but just doesn't seem right to me. What makes you think Amsoil transmission fluid is far superior?

 

Cooler installed. Amsoil FE atf installed. max atf temp 187 degrees on a 87 degree day towing my 2500 lb rv. In all situations the coolant temp greater than atf temp. This thing runs cool. very cool.

 

Excellent work, john.

OF