Hello everyone! I have my 2011 Prius since last April, it has 112k miles on it. Maybe in February I noticed VERY (very!) slight shuddering when the break pedal is released and ICE is not running. This happens at the moment when the car starts to move and it's hardly noticeable. Doesn't happen all the times and I thought it's because the winter tires - they have some kind of aggressive tread. But last week I put a new set of summer tires (215/45/17) and I noticed the slight vibration/shudder again. I found another strange shudder when the MFD scale is in the middle - when the throttle is slightly pressed. It goes away in the exact moment when the accelerator is released or pressed slightly more. I'm not sure, but I'm almost sure this did not happen before the winter. Do you have any ideas? Engine mounts, transmission?
I'm pretty sure the EGR does not take part in the propelling the car wile it's in EV mode. I've disassembled and cleaned the intake manifold, throttle body and the pipe from the EGR valve and they weren't very dirty. There was some oil below the throttle body, but the carbon deposits in the manifold weren't bad. One thing I'm not sure about is the oil in the transmission. I've changed it with Yacco ATF FE, which covers the Toyota WS standard. This was ~10k miles ago, maybe last May or June.
What's troublesome to me: various third-part companies say their fluid is compatible. But: Toyota says to use only their fluid or risk damage. I've got a vague memory: is the Toyota ATF WS hard to get at your location, and/or crazy expensive?
Only the oil costs ~$100. I agree that there are some brands that would say anything to sell their products, but I have no doubt in Yacco's quality, they're french manufacturer with very good name in the oil industry in Europe. But it's true that it might be something in the oil that this gearbox doesn't like ) Here it is: ATF X FE :: Yacco. It's strange to me that Toyota puts this ATF WS ("World Standard") oil in almost all of their transmissions regardless the type and to me this means that it's not super-special as they're trying to sell it. I couldn't find a tech. spec. for the ATF WS. Does anyone have such an information? Or any other ideas about the shudder? Honestly, I was thinking about replacing it again before the hot summer, the old one last year was very-very dark, almost black, so it would be a good flush.
