I bought it with 203,000 had been sitting on his lot awile. I was told the hybred part of it had been replace with used one with 60,000(by Toyota dealer). Since then I know a little more about how it works but keep forgetting to ask what exactly was replace. Son took the car for a week. and said it was making a rumbling noise. Traded back. Driving home it would rumble load at low speeds. Seemed to be right in the middle of the car. Sometimes it would rmble when you start and then stop. But when driving at highway speed it didn't rumble. It never seemed to be the motor itself. It almost seem to make the most where the second gear would be. Took it to the used dealer and he drove it before diving 30miles to work. It rumbled the same but less or not noticed at higher speed. He thought maybe it was the motor mounts. But was stumped. Dropped it off for the weekend to check it. I picked it up after hours and it rumble on the drive home. Talked to him today and said he tightened the motor mounts, something was still wrong. and we should take to dealership. Which means double everything. Now since I have driven it today around town it only happened a couple of times, It seems to drive fine. For a 20 min drive I could NOT get the rumble to happen like last week. But in that that second gear speed area it seem like sometimes the motor was working harder than usual. I know none of this sounds good. Going to the deallership in two days. I would like to know more than I do now before going there. Any guesses??
Let's go over the hypothesis that need to be tested: front bearing - tends to come and go with left or right turn. Speed related, the wheel hub will get hot/warm from the increased friction. Probably a $500 repair at a shop. CVT joint - tends to come and go independent of turns. Often shows up as a torn grease cover and worst case, a failed, leaking transaxle seal (and loss of transaxle oil.) Another $500 repair but needs to include dropping the transaxle pan, inspecting for metal shavings, and changing the oil. shorting MG2 stator - a speed linked hum, the frequency changes with speed and is there either in "N" or "D" with MG2 having much hotter temperatures than MG1. Car can continue to operate but it is a major repair, over $1,000. GOOD LUCK! Bob Wilson
I would keep driving it for a week or two to see if it doesn't stop on its own. Sometimes when a car sits, it causes problems. Sometimes those problems go away as you drive it regularly. If it doesn't go away, then take it to the dealership and... if it doesn't go away, see bWilson's third bullet. Confirm this by getting to the speed where it makes the hum and shift to N (neutral) to see if the noise is there in N and D. Report the results to us.
