Pros and cons of buying a car with a CVT transmission
Many modern cars use a continuously variable transmission or CVT. The CVT technology is clever and simple, but it has its drawbacks. Let's look at the pros and cons and see how the CVT works. Here, we are only talking about the mechanical CVT with a variator; the electronic CVT used in Toyota Prius and other hybrid vehicles is completely different and is not covered here.
The key component of the CVT is a variator.
Audi Variable Automatic Gearbox (CVT) See larger photo
It consists of the chain running between two pulleys (some CVTs use a steel belt instead of a chain). Each pulley is made of two cones facing each other. The working surface of the cones is smooth. The size of each pulley can be changed by pushing the cones towards or away from each other using hydraulic pressure. The hydraulic pressure is generated by an oil pump.
Let's look at this Audi CVT in the illustration. The engine runs the pulley set 1. The pulley set 2 is connected via the differential to the drive wheels. Right now the cones of the pulley set 1 are pulled away from each other, while the cones of the pulley set 2 are squeezed together. This equals to the low (1-st) gear in a regular transmission. As the vehicle accelerates, the transmission "upshifts" by gradually increasing the size of the pulley set 1 and reducing the size of the pulley set 2. See the illustration below.
What are the pros and cons of the CVT transmission?
High and Low gear of the CVT transmission
One of the main drawbacks of the CVT is limited torque capacity. Because the surfaces of the cones are smooth, the cones have to squeeze the belt or chain with a great force. If an engine has too much torque, the belt or chain can slip.
Manufacturers are working on ways to increase the torque capacity of the CVTs, but for now it's limited. This is the reason you don't see CVTs in pickup trucks and muscle cars, where the engine torque is much higher. Auto makers program CVTs to keep the engine rpms higher on acceleration to reduce the load on the CVT variator. That's why many reviewers often mention a louder engine noise and slower acceleration of the CVTs.
Another minus is that CVTs are expensive to replace. The CVT unit replacement can cost upwards of $4,000 in some cars.
Of course, the main advantage of the CVT is better fuel economy, especially in city driving. A vehicle with a conventional automatic transmission loses some of the momentum while shifting from one gear into another. The CVT has no fixed gears. It changes the gear ratio seamlessly without losing the momentum. It also has fewer moving parts.
CVTs work well in small and medium cars and SUVs and are better suited for fuel-efficient city driving and moderate load. If you need a car for long commutes, towing or sporty driving, in our opinion, a conventional automatic transmission is a better choice. Of course, many sports car enthusiasts prefer a manual gearbox.
Are CVT transmissions reliable?
The number of CVT complaints varies not only between manufacturers, but even between different model years of the same car. For example, quality of Nissan CVTs has not been consistent. We have seen some of the early Nissan Murano SUVs still going with over 200K, but some other models have problems. For example, according to CarComplaints.com data, the 2013 model year saw a spike in CVT problems for Nissan Altima.
According to this page at Nissan USA website, Nissan has extended the CVT warranty for 2003-2010 models to 10-years /120,000 miles. Chrysler and Mitsubishi also had problems with CVTs in some model years. Mitsubishi did a recall for the CVT issues, read more in this CNet article.
Honda also issued the recall 15V-574 for the 2014-2015 Civic and 2015 Honda Fit.
Subaru has extended the warranty for their CVTs, read more in this Forbes article.
Considering all that, the reliability of CVT transmissions should be judged on a case by case basis. Where can you check the reliability of a particular used car model?
ConsumerReports - to access their ratings online, you would need a paid subscription. You may also find the printed copy of their car buying guide in the book store or local library.
Safercar.gov - follow the Vehicle Owners menu and then Search Safety Problems. If you compare the number of complaints from one model year to another, it's easy to see the model years with the most problems.
CarComplaints.com - you can also see the model years to avoid.
Another life hack is to check the vehicle's trade-in value. What will it tell you? Dealers know which car is good, and which has many problems and they set the trade-in value accordingly. Check the trade-in value at KBB.com or CanadianBlackBook.com and if it's very low compared to similar cars, you know the car is trouble.
When to change the CVT fluid?
Many manufacturers don't list the CVT fluid change for normal driving conditions and only mention it for severe driving conditions.
These conditions might include towing, driving on dusty or muddy roads, or in freezing or very hot temperatures. However, many experts advise changing the CVT fluid more often. If you want to keep the CVT fluid fresh, you can have your dealer check the CVT fluid and change it if needed. For example, the owner's manual for the 2017 Nissan Maxima says:
...request the dealer to inspect the fluid deterioration data using a CONSULT. If the deterioration data is more than 210000, replace the CVT fluid.
CONSULT is the name of the Nissan scan tool.
Often, transmission problems are caused by overheating. For this reason, many automotive enthusiasts recommend upgrading the CVT fluid coolers to keep the fluid from overheating. We found many Youtube videos on this subject.
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