What is special about CVT ATF?

[FordFETruck]

I changed the CVT oil in my brothers Scion Iq today with him, the first CVT I've serviced. He brought me Castrol Transmax ATF/CVT universal fluid. On the back of the jugs, I noticed all of the specs it covers including being compatible for use where Dex VI, Dex III, Mercon SP, LV V and Mercon and a bunch of other non CVT related ATF. I always thought the CVT oil was its own proprietary type of blend, but what is it really and what is really in the bottle? it did make a noticeable difference in the "shift" feel, it's definitely smoother and faster reacting and no whine when it's hot like it had with the old fluid.

 

[JavierH19]

Having a metal band make hard contact with a variable pulley means you can't have it slip but you still need it to be lubricated enough so that metal on metal friction doesn't make it eat itself. So the friction modifiers are where a lot of it is. Also you need it to resist shearing a bit better as cvt transmissions have more friction and thus higher temps and they're known to blacken oil way faster than regular transmissions. You can change the oil in a jatco every 15k and it and the filter will still come out pure black every time. And they don't care too much about having the oil be thin at low temps so the viscosity index is typically lower for it on average compared to atf's.

 

[toyotacarnage]

This is the mystery I'd like to debunk here as well. If Castrol can rate their fluid as CVT/ATF compatible and it has the color red designated, I wonder if it's a marketing hype on the OEM or if there is something truly different between the two fluids.

I do enjoy Castrol's products

 

[D60]

I think it's special because it makes people ask why it's special so we can have a thread every ~6 months:

J

Thread 'What makes CVT fluid special?'

Sep 10, 2024

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.

• Jmoney7269
• Replies: 32
• Forum: ATF, Differential, Trans, Brakes, P/S

• 

 

[bbhero]

This is the mystery I'd like to debunk here as well. If Castrol can rate their fluid as CVT/ATF compatible and it has the color red designated, I wonder if it's a marketing hype on the OEM or if there is something truly different between the two fluids.

I do enjoy Castrol's products

CVT operate upon the coefficient of traction…

While almost all other regular ATF fluid operate upon the coefficient of friction…

Two rather differing ways of the lubricant in those transmissions need to work.

Some of the additive companies claim they have discovered the “magical concoction of additives” that can somehow operate in both these very differing ways CVTs and regular ATFs work. I am not saying that those additive companies claim are wrong. Over a longer period of time will tell whether or not those claims are accurate. I mean in terms of years and mileage up and well over 200k to 300k plus miles utilizing those fluids. On many multiple vehicles.


It’s only me.. And it’s only my thought on this. But I would not consider using a universal CVT/ ATF fluid in a CVT I owned.. .

And… I used Eneos Eco CVT in my 2008 Nissan Altima 2 door coupe and it worked great. Plus it was $12.50 a quart vs $26 a quart for the Nissan CVT from the dealership at the time.

Anyone can use whatever they want in their own vehicles. I don’t care.. I do hope that if someone uses the universal trans fluids that it works well for them and they have no problems with using it.