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In several other threads there's been discussion about the CVT's sometimes odd nuances and the need for religious, perhaps more frequent than prescribed, maintenance intervals. My fluid has come out very dark the last couple of changes, and I'm wondering it the temp is getting too high and an aux trans cooler might help. My former Ridgeline had one, and Civics that are modded out and used for racing, etc also frequently have them added. Would an aux cooler be of any use and help prolong the life of our CVTs or will it cause more harm than good in the event of a breakdown from a warranty perspective?

I certainly cannot disagree with the principles of a cooler running transmission in warmer weather, and since we're talking about the Honda CVTs this would look like a very sensible choice - especially if it is "Honda designed and recommended".

However, it is also my contention that if the ATF filter is changed once in a while and no cooling impediments exist within the transmission (bad valves, solenoids and pump) that the intended cooling ability built-into its design should be more than enough - even for very hot climates.

The other issue I would be concerned about is operation in sub freezing temps and how difficult would it be to keep the transmission warm- especially during the first 5-10 minutes of operation. These CVT's really like to warm up a bit in order to behave smoothly and minimize premature stress and wear.

Finally, as long as the materials used by the cooler do not adversely contaminate the HATF fluid then I would have little to worry about.

Cheers;

MSantos

Sounds almost like you'd want it to be solenoid controlled. Push a button/flip a switch inside the car, and a valve opens/closes the lines to the aux cooler. That way, you can have extra in the summer and normal in the winter.

I've got 58k miles on mine and have trans filter on hand for the next OC. This will be the first filter change for the cvt. How often do you think these should be changed?

If you have it done via the dealership, the technicians are expected to recommend additional measures if the fluid shows visible signs of degradation. These additional measures may include a double or triple refill and/or the change of the filter, and even a preventative burnish step. A software update (if available) is also part of the checklist too.

It is hard to put a mileage interval on this type of maintenance since the conditions these vehicle are operated under can vary so much. That is why dealers are instructed to evaluate and report on the condition of the fluids and issue a recommendation as per best practices.

If you do this type of maintenance yourself then you should be well equipped to duplicate what a good dealer would do. That means an extra set of bottles of new fluid and a filter at hand. Notice my use of the word "good" as there are some dealers that will sadly skip one of more of the above steps. :(

Cheers;

MSantos

I've got 58k miles on mine and have trans filter on hand for the next OC. This will be the first filter change for the cvt. How often do you think these should be changed?

I change transmission fluids every 30k miles period. Be it AT, CVT,,, spit spit or MT. Every third oil change the tranny gets it's maint.

I change transmission fluids every 30k miles period. Be it AT, CVT,,, spit spit or MT. Every third oil change the tranny gets it's maint.

I'm assuming the CVT filter is done as well? I remember you mentioning that after changing your CVT filter a few thousand miles after owning the car it was already filled with crap, correct?

If you have it done via the dealership, the technicians are expected to recommend additional measures if the fluid shows visible signs of degradation. These additional measures may include a double or triple refill and/or the change of the filter, and even a preventative burnish step. A software update (if available) is also part of the checklist too.


WHat exactly is a "burnish?" I know those were done to the 1st gen CVTs, but how are they different from simply changing the fluid?

If you search/scroll through the thread in the following link, someone describes the burnish procedure:

http://cngchat.com/forum/archive/index.php/t-266.html

Have they ever figured out why your transmission fluid turns dark? That seems to be very unusual.

Sounds almost like you'd want it to be solenoid controlled. Push a button/flip a switch inside the car, and a valve opens/closes the lines to the aux cooler. That way, you can have extra in the summer and normal in the winter.

This is not a good idea. You don't want the fluid getting too cool before reentering the transmission. Parts could start to warp due to the temperature difference. This is why you have a thermostat controlling the amount of engine coolant going to the radiator and not a manual switch.

This is not a good idea. You don't want the fluid getting too cool before reentering the transmission. Parts could start to warp due to the temperature difference. This is why you have a thermostat controlling the amount of engine coolant going to the radiator and not a manual switch.

That'd be why I've never really seen anyone talk of it before. Thanks!

Side note to that - I wasn't really envisioning it as a system to use during a drive, but more as a "summer/winter" type switch. Extra cooler on in the summer, off in the winter. Would that be acceptable? As long as you don't flip it while driving, you wouldn't be creating wild temperature changes.

I don't believe the CVT should need a cooler unless its seriously undersized for the load.

one example - my Jeep Patriot has a CVT and can tow 1k lbs. To double it to 2k lbs, you can add a factory made -OIL- cooler which connects to the radiator (the oil heat transfers to the coolant/radiator).

But I've never seen any add-ons for cooling the CVT, even for towing, and there have been almost no reports of CVT trouble on the Patriot and they have been around for almost 4 years now with some people at 90k+ miles

So I'm guessing for HCHII, some of the CVT's have a quality issue or the design cannot handle excessive loading and/or high ambient temps.

Correct me if I'm wrong, but there is a stock cooler isn't there, ie: a small radiator with the CVT fluid flowing through. So we're talking about augmenting that, adding an additional cooler?

It seems to me there's something awry with GreenRider's CVT: he's been getting dark, burnt appearance fluid despite frequent changes. I forget if he got the dealership to check it out, or how that panned out.

Hi Mendel;

Yes, you are correct. The HCH-II has a dedicated radiator usually called the "ATF cooler" and it acts as the most effective (but not primary) means of thermal conditioning of the transmission.
The cooler is connected to the CVT via the AFT filter and while it is good to change the filter once in a while, the cooler happens to be a component that also needs to be cleaned once in a while as well since it too is a significant source of fluid contamination.

Augmenting this cooler with another one potentially made with different materials is a source of some concern to me not only because it increases the CATF surface area (more contamination?) but also because there's a chance it is up to driver to control the flow through it instead of the flow being managed by the system as is the case with the OEM cooler.

Cheers

MSantos

Actually, I put off going to the dealership until I could get more info on the latest sw updates. I changed the CVTF about 6K ago so at this point, it's not terrible yet. I may have to wait awile but I want to get it fixed before the Hondacare expires.

Has anyone experienced a total loss of power with the new last sw update? I was driving the HCH II today (my wife usually has it now since she drives into the city) and, when turning left with 5 bars of IMA charge, the car just wouldn't go. It left me hanging in front of oncoming traffic for at least 1-1.5 seconds before it slowly gained speed. Literally, a crawl. The car had been driven with the windows down for 15 minutes or so to cool it off after sitting out at work during the morning and I had the air on at auto 78F with no excessive load on the A/C. THis was the first time the HCH II honestly scared me and made me seriously question its reliability. My wife says this is a common occurrence, along with IMA crashes daily (I had a major one and a smaller one today alone).

All I can say is what-the-heck? The CVT has been an issue for awhile and the dealer has already told me once that there was no problem about 18 months ago. No the car randomly decides not to accelerate at all, even with the ICE?

Obviously there's some shortcomings with the IMA system as it is applied to the HCH II. One would figure Honda would have learned something from Toyota's (perceived) shortcomings on safety, though.

Your loss of power sounds like recallibration symptom: that initial breaking of inertia to get rolling is usually assisted by a generous push from the motor, but during recal. the motor is prevented from giving this boost, resulting in glacial starts, doubly apparent when you really need it, ie: getting through a left turn window.

The cooler is connected to the CVT via the AFT filter and while it is good to change the filter once in a while, the cooler happens to be a component that also needs to be cleaned once in a while as well since it too is a significant source of fluid contamination.

Augmenting this cooler with another one potentially made with different materials is a source of some concern to me not only because it increases the CATF surface area (more contamination?) but also because there's a chance it is up to driver to control the flow through it instead of the flow being managed by the system as is the case with the OEM cooler.

Cheers

MSantos

So, how exactly does one go about flushing out the CVTF cooler then?

Your loss of power sounds like recallibration symptom: that initial breaking of inertia to get rolling is usually assisted by a generous push from the motor, but during recal. the motor is prevented from giving this boost, resulting in glacial starts, doubly apparent when you really need it, ie: getting through a left turn window.

That''s what I initially thought, but the SoC never dropped to 1 or zero as is usually the case right after. It's as though the engine wouldn't rev up, not that the CVT wasn't transmitting the power. Like the ECO mode in my I2 but extremely, extremely exaggerated. The IMA didn't wind up fast either. It just wouldn't go.

So, how exactly does one go about flushing out the CVTF cooler then?

Ah, to do it properly you need an ATF Cooler Cleaner and a brand new Honda filter (spin-on magnetic, non-bypass).

Doing it without the cooler equipment is a serious no-no. Essentially, this is a "must do" step whenever a replacement (or overhauled) transmission is to be installed in the vehicle. It is not a cheap operation and that is why it is not always at the top of the list of things to do for regular maintenance. But depending on the circumstances, it can be a worthwhile "investment" of the $200+ it takes to carry it since it guarantees a thoroughly clean system.

The process involves the heating of CVT fluid in the unit's tank that is fed to the cooler under high pressure (~100psi or so). The pressure must be delivered from a shop grade air pressure system - not the kind of stuff a typical DIY'r usually has in his garage.

Cheers;

MSantos