I have the autoenginuity and I can log some ATF fluid temps under different driving conditions. Anyone interested in knowing how hot these transmissions run? I'm gonna look at it, but I could be a little more thorough and organized if anyone is interested.

Everyone seems to say that these transmission run really hot. Sooo....I intend to put that theory to the test because I don't think they run as hot as everyone thinks they do.

Late,
Trav

 

Well too late. I've already checked it out...

Temp here today is 75ºF. I am going to order some transmission fluid to change it out since I'm surprised the transmission didn't burst into flames after how I drove it just now.

Uhh....folks....this transmission does NOT run on the hot side at all.

I've been driving for an hour now and have saw nothing over 230ºF. That was after 5 back-to-back 40-110mph WOT runs. After that, it took 5 minutes for the transmission temp to fall back down to 190ºF. A steady 72mph will cause the CVT fluid to hang right at 190-195ºF.

The CVT is slower to cool down at lower speeds (duh...less air moving over the cooler). Then again....if you are beating the crap out of it, you probably aren't going to be going 45mph, either.

I drove the crap out of this car just now...WAY rougher than anyone I know would beat a car and it took a lot of effort to get it up to that 230ºF. A 0-100mph WOT acceleration heated the fluid from 185ºF to 195ºF, FYI.

So....the statement that the CVT runs on the hot side is absolutely false.

Just sayin...


Late,
Trav

 

Your contributions are appreciated corolla! Just out of curiosity what did you use to gather temp ratings?

Glad to see that transmition tech isn't going backwards. Just hope changing the cvt fluid is just as easy .

 

Great finding friend.

 

Thanks for the information man! I drive my car hard, especially in the twisties and have caused my trans go hit the "limp mode" a few people here have experienced as well. Now both times when this has happened, I was in full manual mode keeping the revs between 4-6K for about 11 miles straight.

I have a data logger that views real-time data on just about every OBD-II system, yet the trans temp isn't one of them.

 

So what's considered "hot" for an automatic trans? How did you determine that 230 F isn't "hot"? Not doubting you here, just curious. I.e. what does an average automatic trans (non-CVT) typically run at?

 

Firstly, 230ºF IS hot. If it ran temps like that continuously, then we'd have trouble, I'm sure. My basis is that coolant temp hangs right at 195ºF at steady cruise. Engine oil temp hangs right at 195-210ºF. It makes sense to me that the ATF oil should remain around 180-210ºF as a rough ballpark estimate of normal. Even 230ºF isn't all THAT hot.

And I am using the Autoenginuity interface. They have 100% access to all of Nissan's enhanced sensors and onboard tests. So, I can look at pretty much every sensor on the car and get readings from it...enhanced engine, body control module, ABS, airbag, A/V, ADP (drive position....powered seats and steering wheel and whatnot). It can do anything the Consult-III can do. They sometimes just don't add EVERYTHING the Consult has into the program, but if requested, I'd say they would.

Nissan does some weird stuff though with the ATF temps. The FSM talks about the ATF temp sensor, which gives simply a voltage (not much use) and then there is the ATF temp counter, which is....just kind of weird. It spits out a number from 0 to 243 and Nissan includes a chart in the FSM that allows you to convert it to an actual temperature reading. The transmission control module doesn't actually spit out a temp reading...it gives you this bizarre "count" that is converted with the chart (on pg 147 for 2010 model). So, either way...the FSM doesn't indicate exactly what "normal" operating temp is, but there is several times it mentions "ATF temp senor will be this voltage @ 68ºF and this voltage at 176ºF".

Late,
Trav

 

Another little tidbit of info...

Lowest gear ratio is 0.44:1, which it maintains from ~30mph and up. Combine with a differential ratio of 5.173:1 means a final drive ratio of 2.28:1.

 

Thanks for all that technical info man. This is the kind of stuff I like to know about!

 

I thought you shouldn't change the fluid unless it tells you it needs to be... I feel like I have heard both differing opinions on this here. Like some say it should just be checked at 15,000 mile intervals and then other say change it at 30,000 mile intervals...

 

So in other words, looking at the use of a trans cooler wouldn't really be of much benefit unless you drive the car very hard for very long period of time? I would like to know what stop and go driving in 85 degree plus temps would do temp wise to this tranny.

 

Well this is gonna be a long one.

http://www.nicoclub.com/FSM/maxima/2010/TM.pdf

Go there and see page TM-36. It plainly states that the ECM will tell you when the fluid needs to be changed. Whenever anyone on the forum has asked about how often to change the fluid, I point them this direction and say that the ECM will tell you when to change the fluid.

With that being said, the Autoenginuity program can do anything the Consult-III can do. A lot of the Consult-III features are not built into the Autoenginuity scantool program, but they can be. With the latest version 10 update, they added a "Conform CVTF Deterioration Date" option. This simply CLEARS the data....resets the value back to 0. I called the Nissan guru and talked to him about this...he was stumped...called his GTR specialist dude. He said that he would add the option into the program to check the CVTF deterioration date (see what number the ECM is spitting out as opposed to just clearing it without knowing what it is saying). The GTR dude told him that this is just a mileage counter. He said that it does not factor heat and rpm and load into the equation....it's just a simple mileage counter. Either way, he is still going to add this into the program anyhow...he said today or tomorrow.

The short answer is, we will see. As soon as I find out what the deal is with this, I will post it up. If I check my CVTF deterioration date and it is the same number as my odometer says, then we will know the answer for sure.

Bottom line is, though, I think it's a good idea to change the fluid at regular intervals. I am getting some fluid and changing mine in a few days (43,000 mi on the clock). Nissan's severe service schedule only says to inspect the CVT fluid, however the premium service recommends changing fluid every 30,000 miles. Not a bad idea, I don't think. I can afford $75 for fluid every 30K mi. Won't be doing a flush, but changing would be a good idea I think.

Late,
Trav

 

I think you are absolutely correct. Beating the **** out of the transmission saw, at most, 230ºF. I don't think a higher ambient temp is going to make a huge difference in temp at high speeds. I mean, Nissan has obviously designed it to be able to shed heat very quickly (presuming air is flowing over the cooler/radiator). As far as stop and go...I do not know the answer to that, sir, but I will find out when it gets a little warmer here.

My speculation is that the ATF temp will stay just fine. It seemed that the only thing that heats it up is high rpm and high load. I think the answer is all in how you drive the car. If you floor it at every green light, like any other vehicle, you are going to burn it up. Light to moderate acceleration is not going to heat the transmission up beyond what it can handle.

I'll do some experimenting and let ya know in a week or two.

Late,
Trav

 

No problem...same here. Also...just FYI...the torque converter stayed locked THE ENTIRE TIME, except when under ~10mph. Yet another reason I love the CVT. Even as many times as I opened it up and hit xxx mph, the torque converter remained locked at all times. Never unlocked once until my speed was at a creep.

Late,
Trav

 

Corolla - great info and research! Glad you found the site we need more technical people like you.

So question then - when the CVT goes into limp-mode after ******* it (4k rpm max) what would be your suggestions to help? Trans cooler? Or is something else happening that causes the car to go into limp mode?

 

I live in ATL, I drove back to NY, the 1st stretch out of GA, the weather was probably like 100 and thick and humid, not unbearable but Georgia heat, after 2-3 hours of 80-100mph sprited driving and another hour in stop and go traffic I decided to pull off and get gas and food, soon as I slowed down my cars was bogging, to use a word to describe it, it did not want to shift out of 1st, at least that is what it felt like, got gas and food, car sat for 30 minutes, got back in, no pedal feel, gas pedal to the floor, car accelerated extremely slow staying in a low gear, got on the highway, it made it up to 80mph, I had no choice 300 miles from GA, 600 miles from NY, no traffic and the car seemed to accelerate like normal after 20 minutes of driving, guess the highway speeds cooled off the trans I will probably be doing the same drive in 2 months, guess I will see how it reacts, I did the drive during the winter no issues, and no dash lights

 

My brain is weird here and I can't explain it but it seems similar to what a overheated fuel system can experience with vapor lock. Cooling it down seems the only remedy?

 

I never had a trans problem like u guys are explaining thats weird

 

yeah you need to drive the car really hard in moderately hot weather. i never saw it in the winter but had it happen once now that its 70-80 degrees outside. RPMs simply wouldnt go above 4k, I was worried so tried it again after it cooled down and car drove fine

 

Thats crazy interesting tho im ask one of my tech at the dealer see what be says about it

 

Any update on this one? How did your "CVTF deterioration" value compare to your odometer? Did they look close?

How does one change their CVT transmission fluid anyways? I see references to "Flush" and "Change", what's the difference?

 

So no updates. AE did add the ability to check and reset the deterioration data, but it doesnt work. Everytime I have tried it, I just get error from the software. They know about it and it hasnt beem fixed. :-(

The CVT has a drain plug on the bottom. Total capacity is like 10 3/4 quarts. Simple drain and refill will take right at 3 quarts, so you are only getting <1/3rd of the fluid out of there. But given the fact that I sent the fluid off for analysis when I did a drain and refill at 45,000mi, I would say the drain and refill is fine for average driver. I am rough on it and the fluid was in good condition and wear metals looked fine as well.

Lots of people recommend against flushes simply because it stirs up a lot of sediment inside transmission that will float around and eventually find its way into bearings and ultimately leads to transmission crapping out. I wont be flushing mine. I will post link to my fluid analysis so you can see what I am talking about.

Late,
Trav