I recently bought a 2013 Corolla LE (automatic transmission). I am noticing that the car starts rumbling at 2700 RPM and stops rumbling at 3000 RPM (maximum rumbling at 2800 RPM) when speeding up and the same when slowing down. Since the car comes with a 1 month drive-train warranty, I took it to the dealership and the service manager (to whom I reproduced the problem) indicated that it may be an issue with the harmonics. The technician notes "...notice induction sound during 2000-3000 RPM. Checked all intake ducting and clamps. Checked all engine and transmission mounts. All items are in good condition. Could not duplicate customer's concerns at this time.".
The issue is, the vibration is becoming bad and I am afraid it might cost a lot to fix when the 1 month warranty is over (in 10 days).
I would appreciate any pointers on
- How to reproduce the problem more consistently (since the technician "Could not duplicate" the issue).
- Any other likely sources of the problem.
Note: This question discuss a similar issue and suggests mounts as the primary cause. From my technician's notes, it appears the mounts are fine.
Edit: There is no rumbling when the engine is revved to 3000 RPMs and transmission is set to park.