RAV4 rear noise?

I have a 2006 Rav4 and every time I drive my car after it’s been sitting for a while there is a very loud noise coming from the rear of the car, the noise usually lasts about 10 to 20 seconds and only happens when I press on the accelerator, and is always when I go forward, never in reverse. The noise is usually louder when it is humid or it is raining.
Any suggestions as to what this could be and how to fix it would be helpful. Thanks.

It would help if you can try to decribe the noise: whining, scraping, grinding, thumping, banging, etc…?

Since it happens only when you hit the gas in forward gear, I’m guessing something in the drivetrain like a rear differential coupling, or something inside the rear differential.

By the way, there is a known problem with the rear differential on this model/year:

Vehicle: 2006 Toyota RAV4
Nature of Defect:
Bulletin Number:
TSB-0080-13 Bulletin Date:
Jun 2013

Could this be as minor as needing to clean surface rust from the parking brake pads or the rear brakes ? The rain and moisture seem to have some effect.

I wondered about rust on the brakes too, but OP says the noise happens only when accelerating forward, and noise from rusty brakes should happen when the wheels are turning, regardless of whether or not car is accelerating, and regardless of which way the wheels are turning.

The directionality of it makes me think differential.

The noise is a very loud humming.

Humming or a rattling!!!

It could be just a loose heat shield rattling until the heat causes parts to expand and the rattling goes away.
When the engine is cold and before starting, grab the tailpipe and shake it left, right, up & down. You may be able to reproduce the noise and this should confirm the problem.


The noise is like wetting your finger and rubbing it up and down on a large piece of glass like a window or large picture. It is a MOANING sort of sound.

It is NOT a squeak, squeal, whining, scraping, grinding, thumping, banging noise, etc.

We have taken the car to the dealership and they said it is rust on the rotor, nothing they can do about it. I doubt this in that like someone said above it would make the noise going forward or backward. Toyota has been not helpful at all.

Like my daughter said it is more noticeable when the it is very humid or raining outside.

I am curious about the rear differential and what noise that makes?


Thanks for that post jesmed1

@lumberjack, that does sound like a brake pad making a brake rotor resonate with a “moaning” sound. Sometimes that can be cured by removing the brake pads and putting some anti-squeal brake grease on the backside of the pads. Also have the brake caliper slides checked to make sure the brake calipers can slide freely back and forth on the slide pins. If they’re stuck, they can be knocked free and the pins lubricated so the calipers will slide freely.

Take it in to your trusted local mechanic, not a chain store, and have him grease the backs of the rear brake pads and the caliper slides. And if that doesn’t work, you may need to change brake pads (use only OEM pads. Some non-OEM pads will also make a noise like this.)

Rear differential will make more of a growl or high-pitched whine like a jet engine, not a moaning sound.

We have two poster describing the noise. Is this the OP with two handles or someone else?

It’s the OP and her father.

Make sure the rear differential fluid level is correct.

I am the original posters father. We were talking about how on earth to describe the sound it makes. Then it sort of came to me. I have been trying to figure this out for months. Jesmed1 I think you might have the answer. I am gonna check the caliper slides, hopefully this weekend. Not sure with other stuff planned. I will post up if this solves the problem. Thanks for everyone’s thoughts. -Larry

Let us know what you find.