My car has 132,000 miles on it. It has had regular scheduled maintenance at a non-dealer, and all recall fixes. Recently, I noticed a faint growling sound while on a long highway drive. It persisted and may have gotten slightly louder over the course of about 300 miles. The initial diagnosis by my mechanic, during a test drive, was wheel bearings. When I took it in for the work, they did further diagnosis on the lift, and said it was not wheel bearings but the sound was from the transmission. No way to repair, only to replace. I've since done lots of research, and have not found this to be a common problem. Lots of chatter about transaxle fluid, though. I'll have to check with mechanic if this has ever been replaced; I doubt it, since it's not supposed to need it. I had not planned to replace this car until 2016, but a $5,000 transmission job doesn't seem to make sense with 132,000 miles. Do I really have bad bearings? Could it be that the transaxle fluid should be replaced? Is this dangerous to drive? Could it seize up on the road?
I would first check the tires and the exhaust system for the mystery noise. I would also change the transaxle fluid, but highly doubt that's the reason for the noise
get another mechanic to check the tires for cupping and recheck the wheel bearings before you go for the trans. and I would change the trans fluid even if its not the trans making the noise.
I suggest that you replace the transaxle ATF now because it may help and will not hurt. If the noise remains faint, then I would continue to drive the car as-is. You'll get lots of warning with regards to the noise getting worse before you need to take any action. As previously suggested, if the noise gets much worse and you decide that the transaxle is at risk of failing, it would be reasonable to install a used transaxle. This might cost you $2K including labor.
