Impending Transaxle/MG2 Failure?

[slivengood]

Hi everyone,

I have a classic (first gen) Prius, 2001, 136K miles. Several weeks ago (or maybe more!), I noticed increased humming (almost a grinding sound) while driving. At first, I thought it was probably tire noise, as I knew I needed new tires. I now have new tires, and the noise is still there.

Here's what I know: the noise increases with car speed, but is not affected by engine speed. At low speeds, it is not noticeable (say below about 30 mpg). Shifting to neutral does not have any impact. From inside the cabin, the noise appears to be coming from the rear of the car; opening the windows does not appear to indicate that there is any significant noise outside the car. I have not yet had any computer-reported error codes.

So, I turned to these threads and have read about the issues with MG2 and transaxle replacement, so now, of course, I'm worried about this! I've also found in some threads that this might "simply" be a problem with a bearing??? Unfortunately, to me the tone seems consistent a problem with a failing motor, but if it is the transaxle problem, the sound would be from the front, right? I suppose, though, that just because it appears to be emanating from the rear doesn't mean that it actually is.

My plan is to take her in to have the bearings inspected and I guess I'm hoping there actually is a problem there. If not, should I just drive her until I actually have a computer-detected problem, or ???

If I do eventually need a transaxle replacement, are there any repair shops in Southern California (preferably in [Southern] Orange County) that specialize in hybrid/Prius repairs? I've seen several threads mention good independent shops in the Bay Area, but this doesn't help me!

Any thoughts are appreciated!

[krousdb]

My first thought is a wheel bearing. If the noise is coming from the rear, I doubt it is the transaxle, which of course, is in the front.

[tochatihu]

Hi new poster, you definitely should be checking the wheel bearings first. Second step is replace the transaxle fluid and inspect inside its sump. Let's not focus on transaxle electromechanical problems just yet.

Good luck.

[bwilson4web]

Originally Posted by slivengood

. . .
My plan is to take her in to have the bearings inspected and I guess I'm hoping there actually is a problem there. . . .

Any thoughts are appreciated!

Sometimes a failing bearing will change sound on a right or left turn. The same is true of a failed CVT joint. But I would have expected changing the tires to include checking the bearings as well as the brake assembly.

If there is some part rubbing, you should be able to feel the heat in the brake drum. Also, if it is detectable outside of the car, driving by a wall with the windows down should let you hear any reflected sound.

Changing the tranaxle oil is a good idea but be sure to have a clean, dry sample bottle, say an empty, dry water bottle. If the oil looks suspicious, having a sample allows testing later.

GOOD LUCK!

[slivengood]

Diagnosis: right rear wheel bearing. $500 all in Better than a new transaxle !!!!

[jdms2000]

did you find a reliable orange county prius mechanic?

[slivengood]

No independent shop, no.

I had been using San Juan Capistrano Toyota, but they failed to diagnose the problem earlier and I didn't really have a good feeling for them, so I tried Power Toyota (at 5/405, technically Irvine, I guess). Can't really recommend or not recommend them--seems like a typical dealer (overpriced, take-it-or-leave it attitude, having to go through a salesman, I mean service advisor, instead of talking to the actual mechanic, but they fixed the problem and I do have confidence that it was done right).

[ibmindless]

Are you kidding me?!! $500 for a wheel bearing?!!

[ibmindless]

I just checked my ipod app for getting repair estimates. Replacing a single rear wheel bearing in San Diego runs $234 to $432. Parts run $83 to $240 and labor is $151 to $192. Naturally, a dealer is expected to run more towards the higher range of estimates. The app says there is quite a wide range in prices for this repair and to therefore get several estimates from various garages/dealers.

[slivengood]

IPOD app? You gotta be kidding! Best price for online part is $250 (actual research, not hokey software app); Toyota's list price is $308. Labor rate is $98; book time for what is actually a 30 minute repair is 2 hours. Plus astonishing 8% state sales tax.

SJC Toyota would have been cheaper; their labor rate is slightly less if I remember ($80-ish). Only two dealers in my area, a drive to San Diego wasn't really in the cards.

No independent shop that I know of near me will touch hybrids, that's why I asked on this board for a recommendation, but nobody offered anything.