PSA - eCVTs are NOT the same as belt or chain-driven CVTs

[KGMtech]

I

Here are some of the relevant points but I don't have time to verify all the details right now:

- result of the class action lawsuits against Nissan was a non-admission of fault and a warranty extension to 10 years & extended miles / kms
- there are many TSBs regarding CVT troublshooting that evolved in time, from fluid / filter change to rebuild to replacing the valve body to replacing the whole CVT
- the TSBs (at some point) reference that the TCU needs to be updated
- our CVT failed at ~ 7 years and was replaced at a Nissan dealer
- I started servicing the CVT / fluid at ~ 9 years (2 years on new CVT), fluids used were "OEM" CVT (not from Nissan), Valvoline MaxLife, MotoMaster CVT, Amsoil CVT
- over the last 3 years I've been using the $5 CVTz50 app to monitor CVT temps / values
- I discovered how to check / verify TCU firmware using the app and Nissan tech site, our firmware was still original (2010)
- contacted 10+ dealers in my area about firmware update and had response of: $200-$600 / "we do not recommend" / "will not correct any problems" / "why would you want to do that"
- using the Nissan tech site was able to identify compatible TCU numbers that required no updates, found one on ebay for $100, purchased & installed
- noticed on CVTz50 that our minimum SEC Pressure (secondary circuit, hydraulic pressure) was now 0.35MPa while cruising hot whereas on the old 2010 TCUs (I have two) it would drop to 0.25MPa and that's when "slipping" would start to occur
- I believe the slipping is due to insufficient secondary pressure (possibly from the lockup clutch, could be fwd, lockup, or belt slipping)
- the purpose of minimizing the secondary circuit hydraulic pressure is part of the energy saving strategy, as is the the use of a CVT fluid warmer, you can read about this in JATCO tech reports
- we have not experienced any slipping since the TCU replacement
- Nissan implemented CVT fluid warmers in most (all?) of their CVT equipped vehicles but very few had a cooler or cooler option
- our CVT will reliably "overheat" during summer weather and long trips, this causes the "deterioration" count in the TCU to increase once the fluid exceeds 89C
- Nissan flew too close to the sun by minimizing hydraulic pressure to improve fuel economy, minimizing the need for CVT fluid change / service, and not providing proper overheat protection
- Nissan "did no wrong" but did offer extended warrany replacements, unfortuneately our dealer neglected to update the TCU at that time

That being said, I'm due for a CVT service now and this will be the first one since the TCU update along with the use of Amsoil CVT fluid and extra magnets in the pan. Hopefully I'll have a post up about this in the coming weeks.

I'm surprised that your CVT reliably overheats in the summer, you are in Ontario and yes we see 34C in summer it's not everyday and usually if you are moving on the hot highway the CVT will cool down pretty well. I also have the CVTz50 app and neither my old Maxima, my current QX60 or my wife's 21 Rogue have registered any fluid degradation.

 

[martinq]

I

I'm surprised that your CVT reliably overheats in the summer, you are in Ontario and yes we see 34C in summer it's not everyday and usually if you are moving on the hot highway the CVT will cool down pretty well. I also have the CVTz50 app and neither my old Maxima, my current QX60 or my wife's 21 Rogue have registered any fluid degradation.

On long, 1hr+ trips I will monitor the temperature and if we have the AC on (summer time) the CVT temp will exceed the engine oil temp. It might take 45mins, or stuck in traffic, or uphill climbs. Once the CVT is "HOT" it can take 10 mins of cruising before it comes back down to engine oil temp, much longer if stopped.

I'm sure I could improve the situation by replacing the coolant & AC rads but the CVT needs to have a proper cooling circuit for use in 25C+ weather.

Over the past year or so our degradation count is now at 842. I'll reset it at next service and take notes.

 

[D1dad]

What do you consider overheating? My 18 rogue has hit 225 climbing mountains in July yet my 21 altima has never been higher than 205. Now my wifes 24 altima will live in the 205-230 range. I had a tech talk to the service line and they tuned the newer cvts to run hotter to burn off condensation, which doesn't really ease my mind. I also verified the same temps on a 25 altima rental I had in NYC last summer. I still say that a lot of the early failures, in addition to some design issues, was crap ns2 fluid. I've ran my 09 altima on ns3 since Nissan replaced the cvt and its still pulling like new @ 150K

On long, 1hr+ trips I will monitor the temperature and if we have the AC on (summer time) the CVT temp will exceed the engine oil temp. It might take 45mins, or stuck in traffic, or uphill climbs. Once the CVT is "HOT" it can take 10 mins of cruising before it comes back down to engine oil temp, much longer if stopped.

I'm sure I could improve the situation by replacing the coolant & AC rads but the CVT needs to have a proper cooling circuit for use in 25C+ weather.

Over the past year or so our degradation count is now at 842. I'll reset it at next service and take notes.

 

[martinq]

What do you consider overheating? My 18 rogue has hit 225 climbing mountains in July yet my 21 altima has never been higher than 205. Now my wifes 24 altima will live in the 205-230 range. I had a tech talk to the service line and they tuned the newer cvts to run hotter to burn off condensation, which doesn't really ease my mind. I also verified the same temps on a 25 altima rental I had in NYC last summer. I still say that a lot of the early failures, in addition to some design issues, was crap ns2 fluid. I've ran my 09 altima on ns3 since Nissan replaced the cvt and its still pulling like new @ 150K

In my application (Nissan Cube, JATCO RE0F08B / JF009E) the TCU will increase the "Deterioration Date" counter once the fluid reaches 90C / 194F. This indicates to me that something is non optimal at this temperature and the fluid would "last longer" if it never exceeded 90C.

Nissan states the CVT maintenance is limited to CVT fluid inspection every year / 24k km / 15k miles, under severe service (Schedule 1), and to "change if necessary". To check the fluid, use the CONSULT-III to read the CVTF DETERIORATION DATE value from the TCU.

“CVTF DETERIORATION DATE”
More than 210000:
- It is necessary to change CVT fluid.
Less than 210000:
- It is not necessary to change CVT fluid.

So according to Nissan, I would never need to change the CVT fluid, under severe / Schedule 1 service, if the fluid temp did not reach / exceed 90C / 194F. This only applies to this application while using Nissan NS2 CVT fluid so I would expect a superior fluid (Valvoline MaxLife, Amsoil CVT, etc) to exceed these markers. I'll take that as a safety buffer.

https://gearboxlist.com/jatco/jf009e/

https://tdreman.com/how-often-should-you-change-nissan-cvt-fluid-what-every-technician-should-know/

 

[D1dad]

In my application (Nissan Cube, JATCO RE0F08B / JF009E) the TCU will increase the "Deterioration Date" counter once the fluid reaches 90C / 194F. This indicates to me that something is non optimal at this temperature and the fluid would "last longer" if it never exceeded 90C.

Nissan states the CVT maintenance is limited to CVT fluid inspection every year / 24k km / 15k miles, under severe service (Schedule 1), and to "change if necessary". To check the fluid, use the CONSULT-III to read the CVTF DETERIORATION DATE value from the TCU.

“CVTF DETERIORATION DATE”
More than 210000:
- It is necessary to change CVT fluid.
Less than 210000:
- It is not necessary to change CVT fluid.

So according to Nissan, I would never need to change the CVT fluid, under severe / Schedule 1 service, if the fluid temp did not reach / exceed 90C / 194F. This only applies to this application while using Nissan NS2 CVT fluid so I would expect a superior fluid (Valvoline MaxLife, Amsoil CVT, etc) to exceed these markers. I'll take that as a safety buffer.

https://gearboxlist.com/jatco/jf009e/

https://tdreman.com/how-often-should-you-change-nissan-cvt-fluid-what-every-technician-should-know/

Precisely why my 09 altima started whining @95k. If memory serves, consult had me well under 100 when they replaced my push to start. I don't have a cooler on any of my cars so change the fluid every spring. Filters get done when the 60k warranty runs out.

 

[bdc101]

The Toyota idea was a marvel of engineering. It's just a planetary gearset! The unfortunate thing is that they called it a CVT at the same time as other CVT technologies were giving CVTs a bad name.

For all you nerds out there. Here is a great simulator designed to illustrate how a Toyota "eCVT" works.
https://eahart.com/prius/psd/

 

[martinq]

Precisely why my 09 altima started whining @95k. If memory serves, consult had me well under 100 when they replaced my push to start. I don't have a cooler on any of my cars so change the fluid every spring. Filters get done when the 60k warranty runs out.

Check your firmware for updates ASAP (you can do it yourself). This is what killed most of the Nissan CVTs aside from poor maintenance.

 

[K2K2]

The Toyota idea was a marvel of engineering. It's just a planetary gearset! The unfortunate thing is that they called it a CVT at the same time as other CVT technologies were giving CVTs a bad name.

For all you nerds out there. Here is a great simulator designed to illustrate how a Toyota "eCVT" works.
https://eahart.com/prius/psd/

100% agree.

Engineering Explained has a great video on bubetube on the eCVT. After watching it my hate has dissipated. Somewhat.

 

[D1dad]

Check your firmware for updates ASAP (you can do it yourself). This is what killed most of the Nissan CVTs aside from poor maintenance.

I have no way to check it. I use a scanguage, which will track cvt temps but doesn't give any other data outside of normal coolant and charging volts. I got to believe that it was updated since it's been years and 150k with no issues.

 

[martinq]

I have no way to check it. I use a scanguage, which will track cvt temps but doesn't give any other data outside of normal coolant and charging volts. I got to believe that it was updated since it's been years and 150k with no issues.

$5 will get you the CVTz50 app and the VeePeak VP11 adapter (or similar) is around $20. This is all I use on the Nissan Cube / Rogue. The demo is free.

 

[D1dad]

$5 will get you the CVTz50 app and the VeePeak VP11 adapter (or similar) is around $20. This is all I use on the Nissan Cube / Rogue. The demo is free.

That's android only is it not? I know a lot of the Nissan forums talk it up. Can you actually update your software or is it diagnostic only?

 

[martinq]

That's android only is it not? I know a lot of the Nissan forums talk it up. Can you actually update your software or is it diagnostic only?

Diagnostic and resets only along with monitoring, datalogging and live graphing (any one PID + speed).

It will tell you your TCU firmware or you can find the TCU in your vehicle and read the label (assuming it has not been updated). It cost me $100 CDN to update my TCU, bought one on eBay based on the label pics. My CVT would soon be toast without the update. No amount of maintenance can compensate for bad firmware.

Yes, Android only.
https://cvtz50.info/en/

 

[martinq]

Here's a screenshot of CVTz50 showing the firmware of the current TCU in the Cube. This firmware version is up to date and can be verified on the Nissan tech site.

31036-1FC2D has no updates pending but the other two TCUs I have (ending in A and B) do. You can check your firmware for updates on the [C-III+ Repro] tab here:

https://www.nissan-techinfo.com/ecm07.aspx

 

[Rust_Belt_Pete]

Toyota ECVT is not even a "transmission"
Its a single set of planetary gears. Mechanically speaking this is simpler and more reliable than a manual or automatic transmission.