2005 Toyota Solara 4 cylinder, 4 speed automatic.
I just noticed today what sounds like a very faint humming sound coming from the drivers side of the car from either the engine bay or underneath. Hard to tell but it’s definitely somewhere on the drivers side. Best way I can describe the hum is the same pitch as a leaf blower except volume wise, it’s 50 times more quiet.
The hum is only audible when going 20 mph or less. Over 20 mph I cannot hear it, but maybe that’s because of road noise.
In any case, the hum occurs intermittently (sometimes it happens and sometimes it doesn’t, but usually does) and starts becoming audible when coasting to a stop once the car gets below 20 mph. Or it also becomes audible when accelerating up from a stop up to 15-20 mph or so then goes away or becomes inaudible.
What I have also observed is the humming noise will disappear completely 100% of the time when the car comes to a complete stop. Even if I’m slowing down, decelerating, coasting or braking or moving at any speed from 1-20 mph I still hear the hum until the car is completely stopped. At which point, the noise goes away completely and instantly. Again, however, if I’m going any speed 1-20 mph I usually hear it 8/10 times…
When I do hear the noise, it never changes in volume or pitch. It does sometimes cut in and out and occur intermittently, but it’s only audible at slower speeds between 1-20 mph - and only when the the car stops completely to 0 mph, the noise goes away the instant the car comes to a complete stop. Instantly.
I suspect this may be something to do with the transmission. I don’t believe I heard this noise when I first got the car. I just did 2 back to back drain and fills in a span of a week using OEM fluid the first one done a week ago and the 2nd one done today and today I also changed the tranny filter after doing 2nd drain and fill as preventative maintenance.
When I removed the pan to replace filter, there was some dark thick oil in the pan, which I cleaned completely including the magnets. A few metal shavings but definitely nothing alarming.
When I first got the car, the fluid was dark brown with just a hint of red. But definitely not burnt/black. So I figured it wouldn’t hurt anything to change fluid and filter.
I don’t believe I heard the noise after the first drain and fill I did a week ago, (however it’s hard to say for sure since the hum is pretty quiet, plus I may just be becoming hyperaware of any noises this car makes now since there’s been quite a few lol).
But anyway, I believe the humming noise started today when I drove it for the first time after doing the 2nd drain and fill and filter replacement.
All the gears shift perfectly fine and no slipping, no delayed shifts, no check engine light and fluid is now bright red when I check and at the correct level - with brand new filter. Very strange…And yes I’m sure the fluid is at the correct level and I’m checking it correctly per the owners manual…when I check the tranny fluid level I warm the car up for 20 minutes driving it around, then come back and park on a flat level surface, run the car through all the gears a few times P R N D and them check dipstick.