sigh. i keep reading posts from ppl getting the consistent 'hummmm' (aka low hum - not high pitch whine), but when I was in last week for tire rotation and minor warranty work they told me this low hum was "normal" and refused to replace it. It's pretty annoying...
I feel your pain, and I was merely asking for them to listen to the sound and decide for themselves if it was "normal" or not. No expectations going in on them replacing it or not. I could have lived with the noise if they had decided not to replace, but I got excellent service as always.
Couple things to note from my conversations with the service team:
- they said the noise was coming from a bad bearing, which I think is a little odd since the noise was linked to the go pedal. It's not like there is a clutch or anything else that would disengage any rotating parts when power isn't being applied. So either it's a bearing and the combination of a certain speed range and the added vibration of being under power hits just the right frequency or the techs at my service center don't really know what it is. My original theory that it had something to do with the inverter switching doesn't hold a lot of water either since then it would be linked to a certain power level output (like the high pitched noise is/was), not speed.
- according to the techs, Originally these kinds of problems got recorded locally and then the recordings got sent back to engineering to decide if there was something wrong with the drive unit. Recently however the decision making authority has been left to the local techs. In other words its a judgement call on their part and may vary by service center.
- forgot to ask about the drive unit commonality between
60's and the non-performance 85's, but I'm assuming it's just that that level of firmware programming can't be done at a service center.
Also I had my UMC replaced because it was having problems connecting to the car consistently. It looks like I got the newer version that I've seen a few pictures of around here. You can tell the difference between the new and the old by looking at the charge handle. Old has a charge door button that has a gap all the way around, New has a gap only on three sides.