CVT Discussion

[Sierra048]

Great discussion and much appreciated.

Admittedly, I haven't driven any CVT equipped vehicle yet. My wife and I are just starting the process of deciding what we might like and when we might take the plunge. We are getting up in age so towing isn't a factor going forward. We will keep the Frontier for hauling larger items not fit for a smaller vehicle. Since my wife's parents are in poor health in Florida, we will need another vehicle for me to drive while she visits and cares for them. I would accompany her but I have responsiblities here.

Except for a Ford dealership,a Chevy Dealership and a Dodge/Chrysler dealership, we are about two hours away from other brands. Nothing from Dodge excites me. Most of the Chevy offerings have the start/stop technology that I'm just not interested in. I haven't researched Ford offerings as of yet. The Nissan Altima would fit our needs but the Cvt issue has me concerned given possible repeated trips for warranty work should the transmission not hold up. Honda and Mazda I haven't checked out yet.

I'm glad there seems to be a lot of successful CVT ownership in the responses. I did correspond with a Sales Manager from a Nissan dealership that admitted there were issues with earlier versions of the CVT but they have been sorted out now. I'd like to believe him but I have read of issues with more recent versions as well. One big issue, at least from earlier accounts, was that you couldn't get parts for these transmissions unless you cannibalized another unit. No parts were available through Nissan parts departments.

I know all brands have their issues but I'd be extremely interested to find out the root causes of all the Nissan failures I read about. Finally, since I haven't checked out all available brands, what small to mid-size cars still use a non-CVT transmission?

 

[slacktide_bitog]

I can vouch for the CVT in the 2013 Accord being good. The one I drove has over 200k with no problems

The only other CVT I've driven is a brand new Spark, but the car is still too new to gauge any reliability assessment on

 

[Trav]

Originally Posted By: JTK
Like'em or not, it doesn't look like CVTs are going anywhere.


Of course they are not going anywhere when the manufacturers don't want you to have any other option so they don't offer one.
They are using the US market as a dumping ground for these units, in other parts of the world they still offer sticks and regular automatics in cars that in the US are CVT only.

Look at these Toyota Corolla, one with a stick and the other with slide and drive. The CVT gets one tenth of a liter per 100km better fuel economy (you can spit more than that). It gets 2 grams less CO2 per Km but 0-60 times are 1.1 seconds slower and top speed is 10Kmh less than the stick.

In reality there is no advantages to the CVT only lower performance in an already anemic car. It cost more to buy and reliability is questionable. The stick is still in production but they refuse to offer it to US customers.
IMO the only way to knock these companies back to reality and give customers what they want is don't buy their product, let them eat these. I for one will never own a CVT even if I have to import manual unit and retrofit it.

https://www.toyota.de/automobile/corolla...anceOption=cash

 

[Sierra048]

Originally Posted By: Trav
Originally Posted By: JTK
Like'em or not, it doesn't look like CVTs are going anywhere.


Of course they are not going anywhere when the manufacturers don't want you to have any other option so they don't offer one.
They are using the US market as a dumping ground for these units, in other parts of the world they still offer sticks and regular automatics in cars that in the US are CVT only.

Look at these Toyota Corolla, one with a stick and the other with slide and drive. The CVT gets one tenth of a liter per 100km better fuel economy (you can spit more than that). It gets 2 grams less CO2 per Km but 0-60 times are 1.1 seconds slower and top speed is 10Kmh less than the stick.

In reality there is no advantages to the CVT only lower performance in an already anemic car. It cost more to buy and reliability is questionable. The stick is still in production but they refuse to offer it to US customers.
IMO the only way to knock these companies back to reality and give customers what they want is don't buy their product, let them eat these. I for one will never own a CVT even if I have to import manual unit and retrofit it.

https://www.toyota.de/automobile/corolla...anceOption=cash

Trav,

Have you heard or read any analysis of why, in this instance, the Nissan CVTs, were failing in such large numbers, at least the earlier versions? I've watched videos of how they work and I'm wondering what exactly keeps the chains/belts from slipping on the cones. Many of the complaints I read mentioned slipping. Are the cones covered in CVT fluid? It seems counter-intuitive to me that adding a lubricant to that set up would facilitate a belt "grabbing" the cone surface. And finally, what does cause the friction that keeps a belt from slipping? Thanks.

 

[demarpaint]

Originally Posted By: Trav
Originally Posted By: JTK
Like'em or not, it doesn't look like CVTs are going anywhere.


Of course they are not going anywhere when the manufacturers don't want you to have any other option so they don't offer one.
They are using the US market as a dumping ground for these units, in other parts of the world they still offer sticks and regular automatics in cars that in the US are CVT only.

Look at these Toyota Corolla, one with a stick and the other with slide and drive. The CVT gets one tenth of a liter per 100km better fuel economy (you can spit more than that). It gets 2 grams less CO2 per Km but 0-60 times are 1.1 seconds slower and top speed is 10Kmh less than the stick.

In reality there is no advantages to the CVT only lower performance in an already anemic car. It cost more to buy and reliability is questionable. The stick is still in production but they refuse to offer it to US customers.
IMO the only way to knock these companies back to reality and give customers what they want is don't buy their product, let them eat these. I for one will never own a CVT even if I have to import manual unit and retrofit it.

https://www.toyota.de/automobile/corolla...anceOption=cash

Things like this always interest me. Some may say the transmission doesn't hold up well to the type of use they could see in that market. Others might say the best technology is saved for the US market. Take your pick....

I bet the mfg. has the answer, all we can do is guess.

 

[JTK]

Originally Posted By: Trav
Originally Posted By: JTK
Like'em or not, it doesn't look like CVTs are going anywhere.


Of course they are not going anywhere when the manufacturers don't want you to have any other option so they don't offer one.


I agree, but they're building what sells and that is something with an automatic transmission. I don't think the average consumer even knows or cares their automatic is a CVT or a step-shift for a Corolla or similar.

I know I too would prefer a nice, smooth operating 5 or 6spd manual, but the market speaks louder than us and they build what sells.

 

[JTK]

Originally Posted By: ARCOgraphite
... In 3 speed AT of yore, top gear would be straight through the case with locked shaft with no gear loss - planetaries along for the ride with no reduction.



Sure, but you still had torque converter slippage and all the losses associated with that. This was long before locked TCs.

 

[ARCOgraphite]

Originally Posted By: CKN
Originally Posted By: KrisZ
CVTs have an inherently weaker design. You have a think metal ribbed belt riding on two cones. The forces and surface area involved in keeping the belt riding on the cones is the major problem in them.
If I had one, I would treat it gently and change the fluid often.



Maybe in your view they do-but if they go 200,000 miles-they must not be too weak.

Kris may be like me in the regard that transmissions should be the last thing to fail on a car.
Like my 70 buick with TH400 or the 65 with a super turbine 400 with switch pitch converter.

Back when there were 2 transmission ONE indestructible and one sorta OK. Like C6 /C4, TF727/ ??, THM350/THM400.

 

[KrisZ]

Originally Posted By: Sierra048
Originally Posted By: Trav
Originally Posted By: JTK
Like'em or not, it doesn't look like CVTs are going anywhere.


Of course they are not going anywhere when the manufacturers don't want you to have any other option so they don't offer one.
They are using the US market as a dumping ground for these units, in other parts of the world they still offer sticks and regular automatics in cars that in the US are CVT only.

Look at these Toyota Corolla, one with a stick and the other with slide and drive. The CVT gets one tenth of a liter per 100km better fuel economy (you can spit more than that). It gets 2 grams less CO2 per Km but 0-60 times are 1.1 seconds slower and top speed is 10Kmh less than the stick.

In reality there is no advantages to the CVT only lower performance in an already anemic car. It cost more to buy and reliability is questionable. The stick is still in production but they refuse to offer it to US customers.
IMO the only way to knock these companies back to reality and give customers what they want is don't buy their product, let them eat these. I for one will never own a CVT even if I have to import manual unit and retrofit it.

https://www.toyota.de/automobile/corolla...anceOption=cash

Trav,

Have you heard or read any analysis of why, in this instance, the Nissan CVTs, were failing in such large numbers, at least the earlier versions? I've watched videos of how they work and I'm wondering what exactly keeps the chains/belts from slipping on the cones. Many of the complaints I read mentioned slipping. Are the cones covered in CVT fluid? It seems counter-intuitive to me that adding a lubricant to that set up would facilitate a belt "grabbing" the cone surface. And finally, what does cause the friction that keeps a belt from slipping? Thanks.


The belt is steel and it rides on steel pulleys. The oil is needed to provide friction modifiers and antiwear additives, otherwise the system would wear out too quickly. The pulleys put pressure on the belt, to keep it from sliding and to change the gear ratios via an oil pump, which pumps the CVT fluid.

The whole arrangement is heavily dependant on the oil pump and CVT fluid. That is why these transmissions start whining when they get hot, the loss of viscosity affect the oil pumps ability to maintain the pressure on the cones.

 

[Trav]

Originally Posted By: Sierra048

Trav,

Have you heard or read any analysis of why, in this instance, the Nissan CVTs, were failing in such large numbers, at least the earlier versions? I've watched videos of how they work and I'm wondering what exactly keeps the chains/belts from slipping on the cones. Many of the complaints I read mentioned slipping. Are the cones covered in CVT fluid? It seems counter-intuitive to me that adding a lubricant to that set up would facilitate a belt "grabbing" the cone surface. And finally, what does cause the friction that keeps a belt from slipping? Thanks.


There is more than one system of belt drive, there are pushers, pullers. hydraulic, rollers, etc. The thing belt types all have in common is they need a tremendous amount of pressure on the belt (I have read numbers up to 4 tons of pressure).
Any amount of slip is a death sentence for the unit so anything controlling pressure or fluid breakdown anything that could cause the belt to slip could be the root cause.

Obviously Nissan never found out because their units including the latest replacement units keeps failing. The chain and cones must run in oil to keep them from turning into metal dust, this is why the correct fluid is so important.

The fuel economy benefits are grossly overblown for the consumer (not for the manufacturers who counts drops per car saved by the millions for credit) and is proven by Toyota;s own specs a savings of literally 3-4 ounces over 60 miles is not going to ne notices by anyone. One extra cold start burn more than that.

 

[pezzy669]

I have had a number of Nissan CVT rentals (Sentra, Altima, Maxima, Rogue and Murano).

I honestly don't have any objection to the Nissan CVT in any of the applications but the V6 versions are much more livable than the 4 cylinder versions. Mainly because hearing a V6 near its redline sounds much better than a buzzy 4 cylinder. Incredible fuel economy from all of them.

I will say there was one Altima 2.5 rental I had with ~12k miles on it that was completely gutless and incredibly slow to change to a lower ratio. Early 90's beat up Chevy S10 pickup truck (it was not a Cyclone or anything like that - looked like a base) absolutely wiped the floor with me at a 2 to 1 lane freeway merge and I had the Altima matted, I was a good 2 car lengths behind by the time the lanes merged.

I wouldn't hesitate to get a Nissan CVT as they have had so much time to refine them. But there is the fact I drive super low miles (3-4k year) so any car I buy I probably would not put enough miles on to have major issues before I traded them in.

 

[ttvr4]

The company I work for deploy Nissan vehicles as part of the fleet program. We get a new Nissan vehicle every 60k miles. I am currently driving a 2015 Nissan Altima 2.5L with JATCO CVT with 53k on the odometer. No issues so far. The car averages 35 MPG mixed driving. Prior to the 2015 Altima, I drove a 2012 Nissan Altima 2.5L with JATCO CVT. I returned the '12 Nissan Altima after 60k miles with no issues. We never serviced the CVT as part of the maintenance. I'll be ordering my 3rd Nissan Altima (2019) at the end of this year.

-ttvr4

 

[MolaKule]

Originally Posted By: Sierra048


I've watched videos of how they work and I'm wondering what exactly keeps the chains/belts from slipping on the cones. Many of the complaints I read mentioned slipping. Are the cones covered in CVT fluid? It seems counter-intuitive to me that adding a lubricant to that set up would facilitate a belt "grabbing" the cone surface. And finally, what does cause the friction that keeps a belt from slipping? Thanks.


Belt/Chain CVT's rely on another type of friction or coefficient of friction and that is called the, "Traction Coefficient."

This "Traction Coefficient" has to be within a certain range of values in order to properly transmit power and not let "slippage" occur, so special friction modifiers are part of the chemistry. The rest of the fluid contains base oils, Anti-Wear additives, and other components.

As mentioned in other threads on ATF, whether it be for Step-Shift's or CVT's, ATF's are the most additized fluid in the automotive drivetrain because of these specialized friction modifiers.


https://www.sciencedirect.com/science/article/pii/S0094114X08001432