Strange CVT Behavior - Not Pleased

[msj]

The dealer said he couldn't find anything wrong with my transmission but...I'm really not sure if it is operating as designed. The problem is when I remove my foot from the accelerator and is most noticable between 30 and 40 mph. There is a noticable "drop down" as the transmission disengages. It almost feels like a bounce, not very smooth at all. Also, there is a bump of sorts when I then step lightly on the accelerator. I had trouble demostrating this to the service technician who advised me that what I was feeling was engine braking. Yet, it just doesn't feel right. Perhaps I am not used to a CVT, but I didn't notice it for the first 4000 miles of driving. My car only has 5200 miles. Has anyone else noticed symptoms like these? Any ideas what this "bounce" or "bump" is?

[marlin29311]

What do you mean by "transmission disengages?"

What do you mean by "bump?" What exactly is the car doing?

[msj]

Well, the challange is in describing the symptoms. I can't really state what it is doing, just what it feels like. The "bump" happens when I lightly step on the accelerator. It should be a smooth engagement of the engine. It is not at all. It kind of feels like tolerances are off, like there is a gap in the mechanical components, where there is a gap between components and when they come together there is a bump. More noticiable is when I take my foot off the accelerator. The transition to idle is rough, it feels like components "drop down" or "bounce" . I feel the transmission disengage when I should where I should not really feel anything at all except for what the the technicial calls engine breaking.

The closest I can come is thinking that tolerances are off. Things are just not aligned the way they should be. I don't experience this with my wife's Maxima or my Trailblazer. I think the only reasonable thing to do is to leave the car with the dealer and have someone drive it for a day. It is too hard to demonstrate with a few minutes on the road.

[nametakennow]

The Nissan CVT system utilizes a series of pulleys with rubber-band like belts on them. There's a tendency for them to flex a little coming on and off throttle. This probably explains your problem.

Try our search feature. I know there was a discussion of this shortly after the CVT Sentras first came out.

That said, there were some problems with a motor mount on some CVT-equipped Sentras. There's also an alignment issue with the rear axle. Having both checked under warranty wouldn't be a bad idea. There are threads with a better description of each in the Table of Contents.

[kerrton]

Those are good suggestions of things to check but to me it sure sounds like your CVT isn't working as designed. I think your description of what is happening is crystal clear, it sounds like you get the feeling of hard shifts like in a conventional, that jolt that you know isn't good and definatley isn't the smooth operation of a normal CVT. If you've got lots of warrany left, maybe wait a few weeks and see how things progress, perhaps you'll get better aquainted with how to make it jolt or surge and then you can take it back to the dealer and better demonstrate it for them. But I'd say without a doubt that the CVT isn't working properly, any minor flex in the chain/belt should be imperceptible and wouldn't account for a significant jolt, but anyway some good ideas of other things to check regardless.

[nametakennow]

It's certainly possible. I only intended to shed light on other possibilities first.