Hello,

I have a '15 RX350 with 57,500 miles on it. Yesterday, I was against a wall (at a drive-thru) with my windows down and I noticed a high pitched noise coming from the rear (transmission?). It was only happening when I'm shifted in Drive. When I shifted to Neutral, it stopped, but ~5 seconds after I shifted to Drive, the noise started happening again. Previously, I noticed the same noise when I reverse out of my garage (under a shed so the sound amplifies), and I thought it's probably my brakes since they are pretty thin. Anyone have any idea what this noise could be?

It's under warranty, but everything I take my car to the dealership with any issues, they "couldn't duplicate" any of my issues (they were minor issues). So I prefer to go to the dealership with some more knowledge about this noise before I go to the dealership.

 

The noise is probably from the brake pad wear sensors on your rear brake pads. The rear brakes often wear out first on the RX. It is warning you by making that annoying noise so you get them replaced before they wear down enough to damage your brake rotors. They will probably not cover brake pad replacement under warranty. It is usually considered a wear item, as are wiper blades.

Read your warranty before going to the dealer as they will likely charge twice as much to replace your brake pads as a local independent shop and the dealer is more likely to try and sell you new brake rotors, which you probably do not need. However, you probably should get your brake fluid flushed as it absorbs water and Toyota says to flush or bleed brake fluid every 3 years to protect the brake system from internal wear and maintain brake system performance (being able to stop faster).

If you are in the DC suburbs of Maryland, I can recommend 2 independent shops in Silver Spring, Satellite Motors or Beahm's Auto Repair to consider for a simple brake pad inspection and replacement and brake fluid flush.

 

Is the noise there when sitting still with a transmission engaged or only when moving?

 

If we were discussing the 2016 to present generation of the RX virtually every
symptom the OP mentioned would be caused by the Automatic Parking Brake.
Makes a whirring (or screeching to some!) mechanical noise as the actuator
does what most of us will not do...apply and release the Parking Brake.
The previous generation does not have this feature so I'm unclear what's causing it.

 

I noticed it while reversing out of my garage and while sitting at a drive thru with the transmission in Drive

 

So I know my front brakes are barely surviving (3mm left) and I'm getting those replaced soon. But the rears still have 6mm left according to the dealership. And yes, I'm in Rockville! I'll give both of the stores a call.

 

It may be the front pad sensors you hear but when the sound gets reflected off the walls it appears to come from the rear.
Satellite is more of a Toyota-Lexus specialist. They can even do a transmission fluid exchange. http://satellitemotors.com/

 

OP can you please tell us if the whine is there when you are stopped with the gear in drive ... best place to hear would be in the garage with windows rolled down [standard disclaimer applies about running vehicle with window down in a enclosed space ... silent killer CO].

I would expect some whine as the auto-trans is engaged and the torque converter is fighting the brakes. The difficult part would be establishing if the noise is normal or not.

Salim

 

Hello Salim, yes the noise is when I'm stopped with the gear in drive. It starts a few seconds after I put the gear in drive, which is why I'm sort of worried because if it was when I was braking, then I'd certainly blame my pads because I know they're worn out.

 

I would take a video while in the garage and show it to the dealer. This doesn't sound good. No pun intended.

 

Here is a recording of the whine I hear when it's in reverse and sometimes in drive (I've noticed the noise in Drive once only at the drive-thru).


I put my car into reverse, then neutral, and then back to reverse again (you can see the mirror tilt back and forth) to bring forward the sound of the whine.

 

It could even be the mirror whining as it moves. Try recording while sitting in the car with the windows up.
However, you should have the transmission inspected, maybe the fluid is low or it needs a fluid change, or worse.
If it is AWD you may have low transfer case oil. Both it and the rear differential need an inspection of the fluid levels.