CVT Transmission - Infiniti QX60 Forum
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post #1 of 5 (permalink) Old Today, 09:55 AM Thread Starter
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CVT Transmission

Back in 2013 when this vehicle first came out I was very intrigued, I liked the looks and many innovations of the time. I had concerns mostly co$t but also the CVT, I had no familiarity with the unit and couldn’t grasp its operation/performance. I didn’t buy one back in ‘13 and when I shopped for a 3-row suv in ‘17 I purchased an MDX instead. When that sh*t the bed, I was shopping again 4 months later. I was not really considering a QX still hesitant about the CVT, so what changed. Over two consecutive weeks I was in a Subaru Forester and an Impreza sedan, they also use a CVT, I did more reading and found they co developed this transmission with Nissan. I see many high mileage Subies around that people swear by. In an around this time I spent a month in a nicely trimmed Rogue SUV and was very impressed almost bought one but my wife wanted more frills. So here we are.
Is the CVT different? Yes
Acceleration better with this motor combination than the smaller motor, it goes when you want, yes you hear it and it’s different, no traditional gear shifts just progressively less volume. It doesn’t hunt for a lower gear when you want to merge it just pushes ahead I had a lot of seat time in an MDX with a 9-speed transmission talk about uncertain shifts.
When you slow down it does sound different as well there is no downshifting and you can faintly hear whirring/whining noises, I’m not that well spoken on the engineering of the unit but it doesn’t downshift to help slow you there is something else going on altogether.
The transmission mode selector knob actually does things, try it find where you are comfortable and leave it there. I use standard or eco mostly, snow when necessary.

Overall I have grown accustomed to the CVT and don’t have issues with it. Strange to me as I am an individual who wouldn’t have a daily driver without a clutch until I was 50.
On a separate note the steering is electronic, as many cars of all sizes are it is different as well but not strange or scary. Many modern cars have any combination of steer, brake, accelerate by wire all working in conjunction with the many stability control systems we have.
I sometimes sum it up like this my ‘72 Triumph TR6 had 4 separate fuses, when I replaced that car with a 1994 Mercedes SL320 I realized the difference was huge as that car had 4-separate fuse boxes and literally over 100 fuses and relays to control the systems. Technology is even more prevalent today all across the $ spectrum.
These big Barges are quite nice when you view them with an open mind.
Happy motoring I know I am.
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post #2 of 5 (permalink) Old Today, 12:04 PM
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CVT’s are not that cosmic. I’d guess most of the folks on here had a 10-speed bike back in the day...or perhaps you own a mountain bike now. A 10 speed had two gears on the front sprocket, and 5 gears on the back sprocket. Levers on the handle bars move the chain between the gears on the front and back sprockets, and a derailer (the two little gears next to the back sprocket) keep tension on the chain. If you understand how that works, then conceptually you understand how a CVT works. If you look at the 5 gear wheels on the back sprocket, you’ll notice they make a cone shape. In a CVT the gear wheels you see on a 10 speed bike are replace with cones. Instead of a chain, a belt runs around both cones and is moved to different locations on the front and back cone to change the “gear” ratio. That allows you step on the throttle and the engine can quickly accelerate to the RPM where it has maximum hp and torque, hold that RPM, and then vary the ratio of the CVT “gearing” by moving the belt location on the front and back come to accelerate...kind of like changing gears on a 10 speed bike. Similarly, it can also hold the RPM where the engine is most efficient to minimize fuel consumption and change speed by changing the CVT gear ratio.
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post #3 of 5 (permalink) Old Today, 12:18 PM
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The belt between the two cones does not slip. Instead there is a torque converter between the engine and front cone In the CVT . At a stop, the torque converter disconnects the engine from the front cone. Whe you begin to accelerate, the torque converter allows slip between the front cone and the engine, and gradually tightens until there is no slip. That occurs around 8 miles an hour, and then there no slip between the engine and CVT, only the “continuous” variation of the “gear” ratio in the CVT by moving the location of the CVT belt on the two cones. You can see and sometimes feel the torque converter lock up by looking at the Tachometer, you will see the tach needle suddenly drop around 8 mph, and you might feel a slight shudder, then smooth acceleration. That is all normal. The torque converter will lock as soon as possible to maximize efficiency.
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post #4 of 5 (permalink) Old Today, 12:38 PM
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Issues with CVTs are usually 1 of 3 possibilities: (1). The torque convert does lock smoothly or allow slippage between the engine and CVT when it shouldn’t (can cause shudders); (2) the hydraulics that move the belt position on the two cones don’t hold it steady, and the belt moves up and down the one of the cones. You’ll see the engine RPM fluctuated and may feel shudders; and (3) the belt tensioner doesn’t keep tension on the belt and it slips and results in shudders.
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post #5 of 5 (permalink) Old Today, 05:21 PM Thread Starter
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Thanks Rooster for the straight forward explanation, I thought I would post a thread like this as when I shopped it was hard to find seat of pants info on the CVT. Your explanation does a lot to explain what we may or may not feel when driving, and make sense out of it.
Best Regards
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