What makes CVT fluid special?

[Jmoney7269]

I'm fixing to do a cvt trans fluid change in my 2019 maxima and was curious what kind of oil this actually is? Hydraulic, transmission, a special additive package low viscosity oil? Besides a different color, it smells just like my kubota superUDT² hydraulic/gear oil.

 

[DriveHard]

additives that actually increase the friction "traction" between two rolling parts under pressure...allows smooth surfaces to act like gears.

 

[nascarnation]

additives that actually increase the friction "traction" between two rolling parts under pressure...allows smooth surfaces to act like gears.

Well said. And that's really the challenge of chain drive CVTs, because the concept is not robust to slippage.
It's appealing from a cost and parts count and ratio coverage standpoint, but bad failure modes.
Failing CVTs have been a big problem for Nissan, while Subaru seems to be doing OK with them.

 

[benjy]

Weber Auto has a great vid showing the CVT "chain" NOT for ME!!

 

[JTK]

IMO, it's not as scary and unique as people make it out to be. Reason I say this is I've used Valvoline Maxlife ATF and Castrol Transmax Universal ATF/CVT fluid which are suitable for Nissan NS-3 CVT use and pretty much every other step-shift automatic on the planet. I've used these fluids in two different Nissan CVTs, collectively for around 100K miles. 2017 Nissan Quest and a 2019 Nissan Pathfinder.

 

[oil pan 4]

Whatever it is it has to be extremely shear resistant.

 

[IndyIan]

I'm fixing to do a cvt trans fluid change in my 2019 maxima and was curious what kind of oil this actually is? Hydraulic, transmission, a special additive package low viscosity oil? Besides a different color, it smells just like my kubota superUDT² hydraulic/gear oil.

View attachment 239671

They probably aren't too much different? Both need to have some friction modifiers for wet brakes/clutches/cvt's, similar gear and bearing loads? I looked up the Subaru cvt fluid MSDS for my car and its got a similar viscosity and flash point to SUDT.
I assume Subaru must fine tune each of their cvt fluids for each transmission specifically, which some of their engineers must see a difference in operation and durability, and I think all their fluid is made by idemitsu.
Interestingly, the MSDS sheets show that Total makes SUDT in europe and Ashland makes SUDT in the US. I guess making tractor fluid isn't too difficult to replicate.

 

[nthach]

The trick for CVT fluid is the right amount of friction to allow the wet clutches(TCC and take-off clutch, like a Toyota mCVT and if applicable the one to apply reverse) to operate without binding/shudder but allow high metal-on-metal friction so the CVT’s belt/chain doesn’t slip on the variator pulleys. Afton/Lubrizol might have gotten the combination right for the add packs in MaxLife and Transmax Universal.

 

[MolaKule]

I'm fixing to do a cvt trans fluid change in my 2019 maxima and was curious what kind of oil this actually is? Hydraulic, transmission, a special additive package low viscosity oil? Besides a different color, it smells just like my kubota superUDT² hydraulic/gear oil.

Yes. Any transmission fluid is a hydraulic fluid with a specific additive package as @DriveHard explained above.

 

[Jmoney7269]

Well said. And that's really the challenge of chain drive CVTs, because the concept is not robust to slippage.
It's appealing from a cost and parts count and ratio coverage standpoint, but bad failure modes.
Failing CVTs have been a big problem for Nissan, while Subaru seems to be doing OK with them.

So essentially this thing is likey to fail soon? I inherited this vehicle from my dad and was hoping it would last a couple hundred thousand miles. It has close to 70k now. So should I go trade it in around 100k? I called nissan and they said a transmission swap is north of $6k

 

[GSCJR]

Not likely, the CVT mated with the V6 in your Maxima is fairly reliable; I owned one, see below. Change the fluid and pan filter now, and then every 25k miles. Further, there's a cartridge filter in some fluid coolers that I also recommend changing annually. Good luck!

 

[IndyIan]

So essentially this thing is likey to fail soon? I inherited this vehicle from my dad and was hoping it would last a couple hundred thousand miles. It has close to 70k now. So should I go trade it in around 100k? I called nissan and they said a transmission swap is north of $6k

Hmmm, I just look up what a used transmission is going for, which gives you and idea of what the demand is for them, relative to the rate they are getting scrapped at of course.
Car-part.com has lots available in the $900-$1500 range, so its about average for all transmissions, cvt or not.
RAV4's burn up more transmissions it seems, based on prices, and 2019 2.5 or 3.5 Camry used trans prices are $3k+. So I would assume 2019 Camry's burn up more transmissions than Maxima's. The hybrid camry transmissions are in the $1000-1500 range.

My general impression is that CVT's are pretty good for normal driving, but if you like to jump into your car and go WO while its cold, a cvt has less reserve capability to handle full torque at while the trans fluid is thick, and the belt/chain isn't going to handle any uncontrolled slippage well. Drive it like an adult and change the fluid once in a while and it should go a long time.

 

[Jmoney7269]

The trick for CVT fluid is the right amount of friction to allow the wet clutches(TCC and take-off clutch, like a Toyota mCVT and if applicable the one to apply reverse) to operate without binding/shudder but allow high metal-on-metal friction so the CVT’s belt/chain doesn’t slip on the variator pulleys. Afton/Lubrizol might have gotten the combination right for the add packs in MaxLife and Transmax Universal.

What product is this?

 

[GSCJR]

What product is this?

MaxLife and Transmax Universal.

 

[hrv]

Stick to OEM CVT fluid....Its not like you are changing it every other week...

 

[Pablo]

Stick to OEM CVT fluid....Its not like you are changing it every other week...

Well what if some aftermarket CVTs fluids are actually better than OEM CVT fluid? In all areas. Less/no shearing. Less wear. Better frictional requirement control. Longer fluid life.

Sure, no one is recommending using the WRONG fluid, which could be catastrophic, but there are tested aftermarket fluids on the market now for years that do very well.

 

[hrv]

Well what if some aftermarket CVTs fluids are actually better than OEM CVT fluid? In all areas. Less/no shearing. Less wear. Better frictional requirement control. Longer fluid life.

Sure, no one is recommending using the WRONG fluid, which could be catastrophic, but there are tested aftermarket fluids on the market now for years that do very well.

Thats fine but in my 21 honda HRV I will stick to OEM CVT fluid...along with dual pump fluid for the differential..

 

[Pablo]

Thats fine but in my 21 honda HRV I will stick to OEM CVT fluid...along with dual pump fluid for the differential..

Not sure if the HRV and CRV have the same CVT (I don't think they do) but we've had the Amsoil CVT fluid in the CRV since 2018 when I did a drain and fill a couple times, then drain and fill 3 times in 2021 to assure near 100% Amsoil CVT. No detectable issues in this otherwise very reliable CVT.

 

[martinq]

So essentially this thing is likey to fail soon? I inherited this vehicle from my dad and was hoping it would last a couple hundred thousand miles. It has close to 70k now. So should I go trade it in around 100k? I called nissan and they said a transmission swap is north of $6k

If the CVT fluid hasn't been changed yet then it's way overdue, how much damage is done depends on many things.

I'd recommend pulling the pan off so it can be cleaned along with the magnets. The inlet screen/filter should also be inspected/cleaned/replaced. When you crack loose the screen/filter you'll probably get another 15% of the fluid volume out, removing the pan will also help get more out.

I have used Maxlife ATF in Nissan CVTs and that's the most cost effective where I am but I'm now using Amsoil CVT. Amsoil is still significantly cheaper than the NS2/3 from the dealer and I feel better about the fluid "overheating" with the higher viscosity.

I'd recommend doing an annual pan-drop on the CVT to keep the pan & magnets clean. Once the fluid and magnets keeps clean you can probably go to every 2nd / 3rd year pan-drops, etc.

 

[bbhero]

If the CVT fluid hasn't been changed yet then it's way overdue, how much damage is done depends on many things.

I'd recommend pulling the pan off so it can be cleaned along with the magnets. The inlet screen/filter should also be inspected/cleaned/replaced. When you crack loose the screen/filter you'll probably get another 15% of the fluid volume out, removing the pan will also help get more out.

I have used Maxlife ATF in Nissan CVTs and that's the most cost effective where I am but I'm now using Amsoil CVT. Amsoil is still significantly cheaper than the NS2/3 from the dealer and I feel better about the fluid "overheating" with the higher viscosity.

I'd recommend doing an annual pan-drop on the CVT to keep the pan & magnets clean. Once the fluid and magnets keeps clean you can probably go to every 2nd / 3rd year pan-drops, etc.

Funny… way overdue…

I am not saying what I did was the best idea in the wide world of sports… It wasn’t … I didn’t think about changing the fluid in my Nissan until I did a fair amount of reading on here about doing that.

I didn’t change the CVT fluid in my old Nissan Altima VQ until 284,500 miles. I never did a pan drop.. Justvdrained and refilled it. It had a good drain plug on it.

I bought that car with 39,990 miles on it. I did change it in the car 7 times in the last few years I had the car. Made it to 365,500 miles. Not too shabby.

And I dove that car hard too. Nearly to redline just about every day at least one time a day the whole time I had the car.