CVT 3

[Esjay]

I`m considering purchasing a Nissan Murano w/ a continuously variable transmission. I realize that cvt technology is as old as the light bulb, but most automotive applications until recently have been w/ fairly low horsepower applications. What should the consumer expect in the way of long-term reliability from the Murano cvt, which is hooked up to a fairly potent 3.5 liter V6?

 

[Metalguy]

You should expect to be part of a long-term "proof" that the design works as well as "intended". Being a gambler might help, except I don't see a jackpot as a possible win.

What is wrong with the usual trans? And, having owned Nissans, Toyotas and Hondas, my opinion is that Toy. and Hon. are well ahead of Nis. in engr., etc.

 

[Esjay]

Honda and Toyota are using CVTs, notably in the Civic Hybrid, Toyota Prius. They are smoother, of course, and maybe more efficient in some cases. The Nissan CVT is made by JATCO, not exactly something Nissan came up with on its own.

 

[gvc99]

Honda's CVT's have been on the market for about six years, using a metal belt that transmits power via compression as opposed to tension used in v-belts. The horsepower limit for this belt design is around 100 hp which is why it has only been seen in Civic sized vehicles. VW Audi's design uses belts under tension that are driven off the pins that join the links of the belt together. These CVTs are rated at up to 300 hp. I'm not sure what type the Nissan has. I've had a Honda Civic HX CVT for fours years and its been very reliable, but you must take care to adhere to the manaufacturer's requirements about changing the transission lubricant at the required intervals.

 

[JayMaechtlen]

how much does the extended warranty cost?
Get coverage for somewhat longer than you intend to have the car!

Jay Maechtlen

 

[Slowzuki]

We have plenty of subaru Justys in the area (3 in our yard!) and the metal belt CVT worked great in them for 100 000 km usually. There is a metal problem and the sheeve wears when highway driven at the same speed. We grab them for parts for our 5 spd!

We do own one working one which we are driving and it is a really neat thing to drive! Much nicer than a normal auto!

Ken

 

[JayMaechtlen]

lives only 100k km?

I expect a conventional automatic to do much better than 100k miles!

it's funny- at low speeds, a conventional (lazy american) automatic looks a bit like a cvt, due to the torque converter. Cruise in town, maybe turn 1500-1800 rpm.
Gas it a bit, goes to 2500-3000 immediately, without downshift!
(Buick Regal, 3.8, 4-speed auto.)




Jay Maechtlen

 

[Esjay]

He said 100,000 kilometers, which is more like 60,000 miles.
surely they last longer than that!

 

[HydraMatic]

The Murano is not a belt-and-sheave CVT, but a toroidal CVT. Again, it's not a new idea, but it is a new product and quite different from any OEM's expertise base, so its long-term reliability is risky.

 

[JayMaechtlen]

I know it was 100k KM that was mentioned- I used 100k miles for contrast, to indicate how far from my expectations that figure was.
60k miles is about half what I expect as a reasonable minimum lifetime.
regards

Jay Maechtlen

 

[drwebb]

Check the Nissan Website:

"Xtronic CVT transfers power through two variable pulleys and a high-strength steel belt."

 

[HydraMatic]

Oops. You're right, drwebb. The Xtroid (toroidal CVT) is used in the Nissan Cedric, not the Murano. The Murano CVT is a "traditional" belt-and-sheave system. They're putting 350N-m through a 30mm wide belt, which is quite a bit more torque than anybody's been daring enough to try in the past. Apparently, they think that recent process improvements and design changes in the changes allow it.

 

[drwebb]

Hadn't heard of the Cedric. It's curious design choices because I haven't heard the same capacity concerns about toroidals as belts and chains. At least Toro-Trak chose a SUV as their demo platform at the 2003 SAE Congress. Maybe TT knows something Nissan doesn't- or vice'-versa!

 

[crysta1c1ear]

Jatco's CVT strategy is quite simple. Half toroidal IVT for RWD and belt drive CVT for FWD.

Belt drive CVTs are currently limited to about 500 Nm, see

http://www.luk.de/english/Bibliothek/Download/k7/luk_k7_chap07.pdf

so they would be not useful for anything like a 2000 horsepower 2025 Nm Walley Larson Groundfighter, but should be fine for a housewife driving kids from school to the supermarket in her SUV.

 

[Esjay]

The Murano CVT also offers all wheel drive.
My usual confidence in Nissan tells me that surely they tested this thing in the desert under load. After all, wouldn`t heat be the biggest concern for the belt/

 

[drwebb]

The challenge is maintaining friction at the belt/pulley steel/steel interface while also maintaining wear control. I agree that Nissan must be confident the trannies will last through their warranty periods with recommended periodic maintenance without unacceptable failure rates. Anyone putting anything but the Nissan-recommended ATF in there would be asking for trouble.

I keep meaning to go test-drive one of these when I have the patience to endure the sales pitch. They seem to be selling well in my area. Anyone have any driving impressions of this powertrain? Nissan reportedly wasn't planning to promote the CVT feature of the Murano, so I wonder if it's evident to the driver or not. Some CVTs even have shift-points synthezized in their ECUs to give the customer what they're expecting- !!

 

[bcalcut]

Hey, gvc99, you mention to adhere to manufacturer's requirements about changing the transmission lubricant. Do you have a Nissan Murano and/or do you know what drain interval Nissan is requiring? It seems the fluid is special. Do they want or expect you to change an expensive fluid often?

 

[Prasannao]

I am from Sri Lanka, using a Honda HRV (smaller version of CRV, VTEC 1600cc, 125 BHP) with CVT. The meter reads 50,000 km.

The transmission generates a shudder when starting off from a standstill when the engine is relatively cool. This disappears when the vehicle is driven for about 15 minutes. Fluid change eliminated the problem, but the shudder is back after 2,000 km. I am using Honda Transmission fluid. Is there a special CVT fluid (which is not available with the local distributer) which I should have used? Can someone help?

 

[Slowzuki]

The justy cvt uses regular dextron atf. I should mention the odometer does not have a 6th digit which would suggest a 100,000 km expected life span?

We had 330,000 km on our manual transmission model before it threw a rod so that is our comparison to the CVT model.

Ken

 

[Berblinger]

CVT Transmission Fluid:

There is definitly no general CVT- Fluid like an AT-Fluid out there. Every make and eaven model has their own fluid.

I hardly recommend if you think about flushing:
1) Do it in yours contractors shop
2) Use only this one from the OEM recommended.


Berblinger