"He's just a child!" trans axle problems already?

Ugh. So sorry. Know how that feels.

 

Is it running better now that the fluid was changed again? The "thrumming" is gone?

 

My first thought is that you should "undo" the tire rotation and see what happens.

My second thought is that you should buy new tires of a different make/model than what is currently installed, and see what happens.

My third thought is that you should drive the car as-is for now and see what happens. You may log many miles between the time that you start hearing transaxle noises and the time when the drivetrain is actually impaired.

When that point is reached, then assuming you want to repair the car and find that spending $4,700 on an old Prius is an issue, I suggest you buy a salvage transaxle for ~$500 or so, and have an independent garage or your dealer service dept install it. Good luck.

 

Get a second opinion RE: wheelbearing. I pulled a hub assembly off a scrap car that looked good in every way, turned freely with no wobble or axial play, but only after putting the car on the road did it have issues. I can believe that a tire changer getting rough with the impact gun or using a 2lb hammer to whack a rusted-on wheel would cause a bearing failure, which would be very subtle on physical inspection. I can't see how any on-car service would mess up the trans, which is very robust.

Bearings fail regularly, transaxles do not.

 

It's interesting you say that Seilerts, as I was thinking exactly the same thing . I've seen tire guys go to town on a seized-on wheel with a hammer and it's not a pretty sight.

Without having more quantitative details I'd be careful about this how much significance I'd attach to this. It could simply mean that they looked at the magnetic drain plug and noticed a nice little "fuzz pile", which as those of us who've changed the ATF before know, is not all that terribly unusual.

 

Thanks for keeping us posted. I'm assuming that the transaxle fluid change from the dealer has not helped?

 

Only 75k miles? I don't know what Toyota's rational is with the marathon service interval for transaxle fluid change. Much earlier changes are cheap and easy insurance.

 

Uh.....Mom?
Hate to break it to you, but Rudy's not a kid anymore.

It's like dog years....only worse.

I agree with the above opinions that this isn't a transaxle issue....in fact I'm beginning to suspect that it's more of a short circuit at the dealership between a conscience and a wallet. Since you've already done a fluidectomy (and since the stealership has almost certainly disposed of the "evidence") we'll probably never know how contaminated the original fluid is (was.)
So....
I'm thinking tires.
It's possible that a tire/wheel can be cupped (scalloped) and still be balanced. It's veeeeeeeeeeeeeery common in small, light, front drivers....especially ones that spend a lot of time on the interstate.

Easy way to find out.
Swap Rudy's shoes with a friend's and see if the noise changes or goes away...or as you're planning to do swap his fromt tires with the back.
First rule of Troubleshooting: Always look where you've been.
If you rotate tires and get a thrumming sound? It's not the transaxle!!!

IMHO.....there's a chance that the Toyota dealership in G.H., WA (or wherever you took this car) are crooks, and they would be sprinkling rock salt on the sidewalks down in HELL before I took another healthy car (or any car) back there for another "misdiagnosis".

JMHO....
(Current street value.... waaaaaaaaay less than $0.02)

I respectfully disagree.
Transaxles usually go for six figures before they start to turn gears into shavings. Not a whole lot of combustion occurs in the transaxle, so there's faaaaaaaaaaaar less heat and other contaminants since the TA is a sealed unit.
There's a lot of diverse opinions on this and if you're into the DIY thing, then I would heartily agree that it's better to do more fluid swaps than fewer however (COMMA!) there's a down side.
Sometimes you go to a place like.....AAMCO (which stands for All Automatics Must Come Out) and....suddenly????
Your previously "healthy" car needs a heart/lung transplant!
Rather like Ms Rae up there who took a healthy kid into what I'm Suuuuuuuure is a very reputable and well respected Stealership...

YMMV.....

 

Not Noticeably, but we did get better mileage with the new plugs.

 

Check tires/wheel bearings again. It would be very rare for a Gen2 transaxle to fail at 75k miles. Wheel bearings can make nasty noises but they are easy to swap out. In Gen2 the wheel bearings are modular "bolt in" design with integrated hub, not "press in" style bearings (Gen1 is press in). Gen2 wheel hub easy to install by any shop. Find an independent mechanic who works on Corolla, Camry's etc and have them look at the car. Tell them you hear a noise and would like their opinion of what it is. Don't say "dealer said noise was tranny". Let the shop tell you what they think it is. If problem is wheel bearing/hub assembly decent aftermarket front hub/bearing assemblies are around $100-$150 a side + labor. Shop doesn't need to know anything about Hybrids to install hubs/wheel bearings on a Prius.

 

I would be inclined to swap all the wheels with a local friendly Prius owners to take your car for a drive. If the noise goes away on their tyres then you know the problem. If it doesn't then you know a more expensive problem.

Too much of a coincidence that the noise starts immediately after new tyres are installed. It might even be a bad batch of tyres. What brand are they and are they winter/all season tyres or low rolling resistance ones?

 

The tyres were not new just rotated according to the first post but I'm betting on it being the tyres.

My last set of OEM bridgestones began to make a humming noise that at first I was certain was wheel bearing. The noise even changed with steering direction.

When I changed the tyres still with 4 to 5 mm tread left on them the noise was gone. The real pleasing thing was that new tyres were cheaper than a new wheel bearing.

 

Cool. I was thinking about this the other day when I rotated tires and noticed additional howling.

 

Great news!!! And the dealer was going to steal almost $5,ooo from you.