CVT knocks while shifting

[Rob.Vegan]

I'm not sure if it's always been like this or not but now (in manual mode) when I shift "gears" it makes this kind of knock sound right when I push the shifter up. Everything runs fine but I just noticed that noise today and it kind of scared me because I know the CVT has had some problems before.

I tried making a video of it but you can hardly hear it, my phones mic was kind of drowned by the intake and header But you may be able to hear it. It's just a quick knock sound like stated

http://www.youtube.com/watch?v=w7VbgxJCr2k

[Micron]

Were you playing the throttle to try to keep the engine noise down to hear the "knock?" Any differences in rpm drops between shifts or feel in the pedals? From the video, couldn't see the tach all too well, but it looked like you were shifting around 3K?

[Rob.Vegan]

Ya I was shifting around 3k rpm. When I drive manual cars I usually shift around there so when I kick it into manual mode I keep the same rpm range.

When I was about to shift I let the rpms drop a bit right before I shifted so that the intake/header didn't over power the mic on my phone but it did anyway.

I didn't notice any other thing going wrong. The throttle feels the same, there aren't any leaks that I can see. It doesn't happen only at low rpms though, I brought it up to around 4.5k and shifted and the knock was still there, a little louder I believe too.

I will go back out tonight and try and get a better video of my gauges and with less noise

[Rob.Vegan]

You can't hear it too well in these videos. My phone sucks and I can't think of any other way to try and record it besides my phone or having somebody in the car to hear it personally.

Can you guys with CVT test it out for me. I rev up to about 3-4k and let off the gas, shift up, then apply the throttle again. Will you let me know what kinds of sounds it makes. I don't remember hearing this before about 2 or 3 days ago.

Here's two more videos, you can't really hear it going into 2nd but after that you can get an idea of what I'm talking about. It sounds kind of like I am letting go of the brake abruptly, but keep in mind my foot never leaves the pedal so all this noise is straight from the engine, transmission, and wind noise.

http://www.youtube.com/watch?v=uPjmpXqvDnU

http://www.youtube.com/watch?v=i45S6lXIn3w

[rcboy514]

thats wierd man, at first i thought it was the sound you get when you let off the gas at a mid to high rpm and get that pop sound like the exhaust backfiring. I get that a lot since adding my y-pipe, but the more I listen to it, it sounds like it happens at the exact moment you shift. Could anything have fallen under that flap by the shift handle?

[Rob.Vegan]

I don't see how, but ya something may have fallen down there. When I install my springs this weekend I'll take a look under there and under the car.

The noise seems to get progressively louder with the amount of rpms. But not super loud, if I leave my foot on the gas pedal (giving gas) while shifting I can't hear it

[gatorglaze]

I have the exact same problem, it almost sounds like when you shift, 2 metal things just tap each other doesnt it? If u find out what it is, let me know. This happened after i installed my headers. I also have a fujita intake and stillen exhaust if it makes any diff.

[Rob.Vegan]

I noticed this about a day and a half after I installed my headers. I have an Injen intake and stock exhaust though.

I'll contact dldjros and see if he is having the same problem. But yes it does sound like two metal pieces hitting

[opekone_1988]

I'll test it out today and post tomorrow.

[opekone_1988]

Ok Rob.. so I tested it out just like you said and what seems to be happening to me is "exhaust back pressure crackle" Thats it.. nothing else. That’s the only thing that I heard differently. Hope that helps.
Modified by opekone_1988 at 3:49 PM 10/14/2009

[Rob.Vegan]

I have stock exhaust though, and so didn't think it was that.Plus it doesn't happen when I let off the gas, it's when I shift.

I am not totally sure though, it may be back pressure. I'm going to have someone drive my car for me so I can get a better listen of it

[gatorglaze]

Yeah, i think there might be something hitting each other from the sudden jerk when you let of the gas and shift, at higher gears it doesnt do that but i could be completely wrong. And this is all for the CVT on my car.