Inverter whine or Trans-Axle noise <30 mph?

i think it's normal, but it's hard to diagnose whine on the net. how many miles on her?

 

Pretty much any time you're decelerating you'll hear that "inverter whine", I'd vote normal too.

 

How much braking force do you apply when you use your brakes?

Are they sudden stops or do you allow for a long casual stop?

What screen do you have up most of the time while you are driving? Have you used the HSI display, which can help show you how much charging you are doing while braking?

You may just be braking hard which will elicit the “louder” regen braking sounds.

If you have a friend or someone you know that has a Gen3 Prius that you could compare to?

Hope that helps.

 

Happy belated birthday BTW.

How long have you owned your Prius?

When was the last Brake inspection? How full is your brake fluid reservoir? Brake pad thickness?
Do your rims feel warm after a drive?

Keep us posted .

 

If the reservoir is low, that’s usually a sign that the brakes are wearing.

Do you DIY?

Ever done a brake inspection?

I think it’s worth pulling the wheels off and having a gander at the pads. If you have a dragging brake pad, you’ll get some resistance and see excessive pad wear.

When you say the reservoir was a bit low, how low was it? How much fluid did you add? What Dot fluid did you use?

Hope this helps.

 

Have you been in another Prius or Prius v to compare? What I am trying to get at is if there is something causing resistance, it will cause other components to “work harder” thus leading to “unusual noises”.

Have you changed the transmission fluid? Do you plan on doing so?

I have 170 k miles on our 2010 Prius II and we have over 7mm of pad depth left. I drive ahead and brake very gently using regen braking to its fullest. The brake reservoir is still above full and I have never added fluid since the brake recall several years ago.

I perform regular brake inspections and have a temperature gun that I check the hubs on occasion to ensure they are not hot. I just did the passenger front hub assembly replacement this morning and the pads still are at 7mm and all is well.

I have driven a Prius for over 8.5 years and transmission whine on deceleration is normal. If I brake hard, the noise is amplified.

Hope that helps.

 

When watching and listening to the video, to me the louder portions of the noise occurred when they were slowing down or using the brakes. They did several cycles in less than a minutes where the speed between each cycle hit 40 mph or above.

The display they had up was the energy monitoring screen, which is not very useful for driving or troubleshooting. The Hybrid System Indicator (HSI) display would show where they were on the braking curve, and my guess based off of that video is they were pegged on regen and into friction brake Territory.

Having said this, think about the brakes and transmission working together. If there is more resistance caused by dragging or sticking brakes (you said you “topped up” the brake fluid at 64 k miles) it would be reasonable to say that the other components have to work harder to overcome this new reality,

If components are now working harder, what could happen?

Anything is possible, but the noise I hear sounds normal. I have had to slam on the brakes in our Prius and the transaxle noise gets louder, but I know why.

Another possibility is noise reduction. In our wonderful cars one of the factors that was given lower priority was insulation.

This leads to a lot of noise transferring from various parts of the car to the cabin. In an effort to make the car lighter, weight reduction occurs and the attempt at using lighter weight components creeps in. Are they as effective at dampening the sounds? Not so much. We just recently got a RX450H and the difference between the 2 is night and day with regards to road noise.

But one noise I hear when driving the wife’s RX450h is the transaxle noise when decelerating.

Another example of noise transferring was the wheel bearing hub assembly on our 2010. I changed the front wheel bearing hub assemblies out due to failures and they were getting loud. When I have had other people in the car, they thought it was the tires, but I pulled the assemblies off and sure enough there were not tight and had about a 1/32” of play .

If still concerned that the noise is very loud, I would recommend:

• riding with another Prius owner (preferably a Prius v) to compare
• Change the transaxle fluid and see what the color is and if any metallic materials come out
• Perform a brake inspection as topping up the brake fluid at 64 k miles is not normal for our cars
• Enjoy your new to you Prius

Hope that helps.

 

I know the "pedestrian noise maker" varies with speed and is used at lower speeds. Does it change again when braking?

Just another thought. It is difficult to detect unintentional noises when there is one by (poor) design.

 

Over the years I gradually twigged to this: there's rarely/never any need to top up the brake fluid reservoir. A normally functioning system, where nobody's routinely opening a bleed bolt or whatever, is not going to "consume" brake fluid. The level will drop as pads wear, and if/when pistons are pushed back to accommodate new (thicker) pads, the level will be restored to what it was at the outset.

Topping up doesn't hurt, but is unnecessary, and will likely necessitate basting fluid out at pad replacement, to avoid overflow.

FWIW, a complete replacement of fluid is a good idea, say every 3 years or 30K miles. Toyota Canada now recommends this; IIRC Toyota US has yet to follow suit. It's relatively easy DIY, if you have an assistant, see @NutzAboutBolts video about this pinned in third gen maintenance forum. Note it is 3rd gen hatchback specific, but with a Tech Info subscription you could could find your procedure.

The only comments I would make on the video:

1. Sequence according to Toyota Repair Manual should be Front/Right, Front/Left, Rear/Left and Rear/Right.
2. Mechanical vacuum is not mandatory for the bleeding procedure, and just a simple syringe of some sort is sufficient for basting fluid out of the reservoir. For the latter a very thin tube tip is needed, due to a basket within the reservoir with a small slot opening.
3. "Invalid mode" is required, and well explained in the video. Hopefully the v procedure is the same. Again, a Tech Info subscription would help verify this.

Again, watch/watch/watch the video, lots of tips. It's well done with split screen, which illustrates very well things like the front brake interaction, one person opening/closing the bleed bolt while assistant pushes the brake. My wife and I followed that technique to a T, and it came out fine, no spongy brake, good and firm.

I used two pints of fresh Toyota DOT3 fluid, and a little strategy, using about one pint to for drain/refill of reservoir and front brake bleed, and the second pint (most of it) on the rears. I held back a little, for insurance in case I wanted to fine-tune reservoir level. I noted that level at the outset, and aimed to return it to same at the end. Once I was satisfied, I discarded the small remainder (with my waste-oil recycler): it doesn't store well once opened.

FWIW, I'll attach the Toyota Repair Procedure for regular 3rd gen. Note the verbose/obtuse/obscure method they use to describe the bleed sequence, pretty much the norm for them.

 

in my experience with 5 different hybrids, there's no such thing as 'normal' whine. each had its own characteristics, and also different based on braking and temperature.

 

A coworker calls mine a spaceship due to the noisemaker sound.

 

really? must be a lot louder in the gen 4. i can't hear mine unless i'm in an enclosed space with the window down and engine off.

 

The wife’s RX450h you can just barely hear from the inside . But on the outside it is prevalent .

One of the reasons I am glad I have a 2010 that is minus this “feature” .

 

I'm amazed that you all are so casual about brake fluid changes.

Brake fluid is hygroscopic and absorb water over time. This can damage components in the brake system (think ABS) that are expensive. It can also cause loss of brakes when the water boils and turns to gas as pad/rotor friction gets very hot going down a mountain or when used in extreme conditions like racing. (Some tracks require proof of change within 30 days of the track inspection date.) I'll certainly be changing it at 60k miles since our brake pads wear so slowly if the cars are driven right.

Ray, not changing it in a Mazda my son had which largely just sat around for years cost him his ABS system. We never could get it to work despite replacing multi-hundred $ components. Before you get your creation on the road, do it.