Low humming/rumble after 38 mph. CVT problem???

[Karasu]

Hello everyone.

I´ve had my car for 2 weeks now. (2010, bought it used 29,000 miles on it) When I test drove it, I did not notice anything strange going on because I basically could not drive it at highway speeds due to the city traffic. However, I´ve noticed that after hitting 38 mph and especially between 38 and 50 miles there is a low humming/rumble coming from the front end.
It kind of oscillates a little, like the sound of a plane propeller more or less and there is (was) a very faint vibration of the steering wheel. At first I thought it might be a a bad wheel bearing but I took it to a shop and lifted the car and had a mechanic listen closely to both front wheels while accelerating the car to that speed. I could hear the noise inside, however, two different mechanics failed to hear anything outside the car and near the wheels. I know it is not road/tire noise because it happens even when the car is not touching the ground.
I took it to the Suzuki dealer and had it examined by them. The service person told me that they would perform a transmission reprogram that would solve the noise and I would notice a better performance of the transmission. After they did it, I actually noticed a reduction in the noise but it is still present although considerably less than before. Has anyone noticed a similar sound and is this something normal with this type of transmission? Should I be seriously concerned and demand a better in depth inspection? The car is running fine apart from that, but I´m really worried this could escalate to something more serious and the noise is not letting me fully enjoy my driving experience with my new car.

Sorry for the long post, but I had to describe my concern as clearly as possible.
I hope many of you can chime in with your experiences.

Thank you.

[coref1]

Sorry to hear about your problem. To be honest with my Rockford Fosgate sound system pumping away most of the time I don't hear much else. On the odd occasions i don't have music going I do hear a bit of noise which is most likely from the cvt but I'm haven't worried about it so far as from what I heard it seems to be normal for cvt transmissions.
Hopefully other members can shed a bit more light on it for you.

[Karasu]

Thanks coref1, Yes, I´d like to blast the RF system as well but as soon as I reach that speed I´m muting it to hear what is going on with the car. Let´s see if someone else has had something similar with their cars or if imy case is something isolated and I should be worried about it.,

[Ronzuki]

Are you simply hearing this humming/rumble and not feeling it as well? Could be exhaust notes.

[Karasu]

I don´t think it is related to the exhaust notes because I would find that sound actually pleasing and I can tell you that it can be felt slightly on the steering wheel, especially between 38 and 50 mph. The steering wheel does not wobble, it is just a vibration transmitted to it. Also the sound is kind of cycling. It sounds almost like a propeller plane. That is what lead me to think it could be a bad wheel bearing. What is strange is that below that speed the car feels absolutely flawless.

[Ronzuki]

OK, if you're feeling it at all, and in the steering wheel (even though the car's have electric steering) wheel bearings are a good place to start. SX4s had a rash of wheel bearings failing prematurely. Unfortunately, there are many things that can cause sounds/feelings of that sort. If you are fairly certain it's from the trans, it could be a faulty torque converter. Fluid level been checked? I've had issues in other older used vehicles in the past w/ bad converters as the cause of what you describe, but not until there were many many miles on them and usually from neglect. If I'm not mistaking, I believe the converter on my car locks up at around the low end of the speed range you are talking about when A) I'm in Manual Mode and B) I'm not in to the throttle hard on a long drawn-out acceleration.

Try this:
Run your car in manual mode with soft acceleration and upshift through the 'gears' quickly and take notice of your rpms just before and just after the rumble...see if there's a significant drop-off while you are solid in 5th, you should see the rpms drop off and it will feel almost as though you 'shifted' in to the next higher gear but you didn't....that would be the torque converter. Once you exceed 40-42 mph the car will then accept your manual command to go to 6th. Observe the rumble at that point as well noting if it's the same or worse.

Is your car AWD? That introduces other possibilities that could be perceived to be from 'up front' (transfer case and drive shaft, or if you prefer, propeller shaft).

[Karasu]

Thanks Ronzuki. I´m going to try your suggestion today and see how the car behaves in manual mode.
I took it to the Suzuki dealership last Saturday. I would guess they checked the level of transmission fluid based on the symptoms I described to them but I´m not certain. Is there a way I can check the level myself?

My car is a front wheel drive.

[NJKizashi2]

I have the same problem on my 2010 with cvt. My understanding is that it's the vibration created by the 4-cyl engine running at a low rpm under load. The cvt is programmed for max fuel efficiency and transitions into a higher 'gear' ration as soon as possible.

[Karasu]

Thanks NJKizashi2.
At least there is one more person experiencing the same as me. Have you had your car checked by Suzuki or you are telling me your theory based on your experience? I need to get as much info on this as I can.

[NJKizashi2]

I had it checked by Suzuki and they said everything was fine with the trans. The tech told me that's how it's programmed to run. I use the manual shift sometimes to keep the rpm up above 1500 to prevent the vibration. If you search the forum there were several conversations about this a year or so ago.