Vehicle transmission technology is improving rapidly, giving consumers a wealth of choices. Continuously Variable Transmissions (CVTs) have become a very common option. CVTs are designed to be more fuel efficient than traditional automatic transmissions, but are they reliable?
A CVT transmission, unlike a typical automatic transmission with gears, uses two pulleys held together by a very strong steel belt. The diameter of one of the pulleys continuously adjusts to keep engine rpm at the most efficient level for the particular driving situation. CVTs have no fixed gears like a conventional automatic transmission and eliminate the sensations of gear changes.
The video below made by Toyota shows how a CVT operates differently from a regular automatic and also highlights advantages over a normal auto box in different driving situations:
Brands like Toyota, Nissan, Honda, and Subaru have made CVT transmissions standard in most of their model lineups, while manual transmissions or traditional automatics are optional.
Jake Fisher, Director of Auto Testing at Consumer Reports, says that CVTs have a natural disadvantage because some of them are programmed in such a way that makes consumers think they are broken or working improperly when it is actually not the case.
Conventional eight or nine-speed automatics have a direct, connected feel that makes it easier for consumers to judge their performance. A traditionally programmed CVT with no stepped gear feeling may cause a consumer to misjudge its regular character as a sign of unreliability, which is something Fisher says automakers are working to mitigate.
“Auto manufacturers are consistently improving on their fuel efficiency standards and transmissions like the CVT help to reach those goals but sometimes the results can end up being mixed,” he says. He adds that some applications of CVTs work better than others. The Honda Civic/Accord models, for example, have well-programmed and responsive CVTs that eliminate the dreaded “rubber band effect.” Every CVT detractor you meet will most likely use that phrase at some point in their argument.
What is the rubber band effect? In a typical automatic gearbox, the revs are constantly fluctuating to match your changing speeds as you move through multiple gears. For the driver, there is a connected feel to how your car is putting power onto the road — the transmission changes gears and you feel a bit of a jolt. The CVT transmission takes a different approach. Any calls for more than moderate power makes the engine hold the revs at the highest possible peak until you reach your desired speed.
This approach is supposed to make the vehicle operate at its most efficient level whether cruising or accelerating, but drivers often experience a strange sensation with CVTs. “Because the revs in the vehicle are not necessarily moving in tandem with your level of speed, there is a whole disconnect to the driver operating a car with a CVT. You never have a clear idea how your vehicle is transferring power onto road surfaces,” Fisher says.
He experienced this personally while driving a CVT-equipped car on a snowy surface. There were instances where he was not sure if his wheels were slipping due to the snowy surfaces or if he was just feeling the CVT’s slipping sensation.
Automakers who have fully adopted this transmission are continually making improvements to this technology to make it feel more natural for drivers. Nissan has been using CVTs for quite a while and current units are very different from the early iterations.
Kyle Torrens, Product and Technology Specialist for Nissan, says, “The new generation CVT is now suitable for all of our engine range, achieving an improvement in fuel efficiency of up to 10 percent compared to the standard CVT. One major addition: delivering the feel of a more direct drive.” Nissan tweaks its CVTs often. Issues such as CVT friction and disconnected driving feel are investigated and improved on to create a more pleasant driving experience for customers. Nissan even programmed fake “shift points” for its CVT so drivers can feel it working.
Nissan also uses an algorithm to calculate the “wear” placed on the CVT and the fluid. Things such as miles, duty cycles, loads etc. are considered when formulating CVT fluid deterioration date. This is not unlike the algorithm method many manufacturers with CVT transmission vehicles use to determine CVT fluid replacement intervals.
Victor Paredes, a service advisor at Bay Ridge Nissan, New York, is familiar with the peculiarities of a CVT. “The cost of a CVT transmission flush is approximately 15 to 20 percent higher than that of a conventional automatic transmission flush. Also, despite lacking physical gears within the system, the intricate setup of pulleys and belts actually make the transmission have to work in a more synchronized way than a regular automatic transmission would.”
This means that more things could go wrong quicker with a CVT because there are more repeated movements of parts within the system and wear and tear can happen quicker than in other types of transmissions, which means durability and reliability might not be as good as, say, a seven-speed automatic in the long-term.
The Verdict: Are CVT Transmissions Reliable?
At the end of the day, it becomes more of a question of are CVT transmissions more “reliably” better to drive than a question of total mechanical reliability and that all comes down to consumer preferences.
Even more importantly, CVT transmissions have a strict and delicate service maintenance schedule that customers should try to adhere to. Treating a CVT transmission like a regular automatic transmission can cause reliability issues down the road that can end up making the transmission more costly to repair than a conventional automatic. Proper maintenance goes a long way into extending a transmission’s life, whether it’s a CVT or a traditional one.