Hi folks

Our 40k-mile 2013 AWD has developed a weird noise that we are having a hard time figuring out. Showed the vehicle to two independents and they said it is probably something minor, like a rubber part in suspension and gave us the green light to continue driving it. Vehicle was on a lift and most of the critical bolts were checked to no avail.

This appears to be the same kind of noise that is similar when a wheel you drive into a small but deep pothole, or if the transmission has a very rough engagement into a gear. From lack of better words lol but when driving, it appears from around right (passenger) rear wheel area. The problem can be reproduced mostly reliably and appears vehicle changes motion (from park to drive, like backing out of driveway from being parked), or from a street light. Sometimes this comes on in straight forward motion at moderate (up to 40mph) speeds after applying fair amount of throttle to accelerate. May not be related to speed but not hearing this at highway speeds.

Any ideas before taking her to stealer? Suspect this not covered by 70k mi powertrain wtty.

 

So it's a "clunking" type of noise you're hearing??

 

I am thinking it is more of a "thud" muted type of a noise and not directly metal on metal?

 

Is the noise coupled with motion... like the transmission example you mentioned comes with a jerk that is felt?

I am suspecting that since a shop has checked, then you would NOT be feeling a jerk ... all suspension items have checkd out good.

If so, then look at the contents and things attached to the vehicle.
We once had a rolling soda can which would make a thud sound.

So I would start by emptying out the hatch, all the way to the spare tire.
Try folding the back seat, buckle the seat belts etc. Have some one sit in the hatch to zero in to the source of sound and drive around the parking lot. Tracing the source of sound can be difficult by stereo-hearing as you get reflections, but you help can touch various panels to sense where the vibration starts.

Salim

 

This is a stretch but it could be that one of the bushings in the rear trailing arms became "unseated".. I had this happen on our 15 F Sport and on a rare occasion I would hear a slight thud when shifting between reverse and drive. But the main noise was a creaking sound that was very noticeable at low speeds going over speed bumps.

Now you may think I'm nuts but have your motor mounts checked. Although the sound seems like it's coming from the rear, as we know sound does travel, and since you said the noise is mostly noticeable when switching out of park it made think of this.. And since you're having the RX checked anyway why not have the mounts checked.

Keep us posted..

 

Thank you guys. No creaking sound at all...will let you know after fixing it if can figure this out

 

Still trying to troubleshoot...took her to Toyota dealer for an oil change and asked them to take a look. SA pointed to the following TSB: https://static.nhtsa.gov/odi/tsbs/20...61740-2273.pdf however my symptoms are a different as the noise appears under acceleration rather than braking.

 

The TSB says the noise can occur either moving forward or braking and that is why the Toyota dealer professional mechanics who diagnose such stuff every day pointed you in this direction. I would take this information to a Lexus dealer and have them inspect it for the noise. It will be a free fix if it falls under the TSB.
I have had similar noise in my 2008 ES350 and Lexus later had a similar TSB for the front brakes that eliminated the noise.
I would eliminate the professionally diagnosed likely cause before second guessing them and continuing to try and find another cause.

 

The TSB says it is only covered during the 4/50 bumper to bumper wtty; called local Lexus dealer and they said the same. Chances are I would get milked for $$$ heavily if went to dealer so made an appt in 2 weeks to see local Lexus/Toyota indy specialist

 

Well the TSB identifies which parts are needed based on VIN. You could determine which ones you need, then price out and purchase the parts at one of the discount online OEM parts places such as www.mylparts.com or www.lexuspartsnow.com and have an independent shop install them. Brakes are one of the easiest parts of the vehicle to replace.

The most expensive part would be if you needed new mounting brackets and I priced them at $82 each https://www.lexuspartsnow.com/parts/...821-0e100.html

The rest of the parts are mostly what you would replace doing a brake job and are inexpensive.

Are you near DC and if so are you going to Satellite Motors? A friend takes her RAV4 there.

 

Update: the problem is still there, almost 10k mi later. Had the RX on a lift at three different places, completed the TSB, to no avail. Indy mech tightened up the suspension (not that it was loose) it may helped a bit.

 

I recall the ES350 brake TSB was to install more or thicker brake pad backing shims. Maybe if you added extra shims to the back of your brake pads the noise would decrease because there would be less slop or play around the pads.

 

I doubt it will fix this. Already replaced rear brake caliper brackets and shims as part of the TSB. There is no pad play, this is something else. Just hoping it is not a differential.

 

I trust they have ruled out bad constant velocity joints in the axles and bad U-joints in the driveshaft? Are there any big rubber doughnut things supporting the driveshaft or a center bearing? I do not recall and may crawl under mine to look around.

 

Sorry that I am nitpicking your post. Shim is technically an object to fill a gap. The brake pad shims do that too, but there is a difference. As the pads wear out, the pistons move out too and the gap is kept constant. So what causes the gap .. the rotating disc has a wobble and that pushes the pads back when the hydraulic pressure is relieved. A machinist for sure, but a mechanic can measure the run-out (wobble) and that can be looked up in the service manual to make sure it is in tolerance. So adding shims or removing shims will not change the free spacing between pads and disc.

So how does the shims help noise?
piston - shim - grease -pad - gap/no_gap - disc - gap/no_gap - pad - grease - shim - flaoting_end_of_caliper

As the gap changes to no_gap (or the reverse operation) due to the run out the assemble starts vibrating (moves with the run-out). Different material and thickness will make a difference in vibration.

Salim