Transaxle Seal Leak - How common, how dangerous?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Estes Kefauver, Jun 16, 2017.

  1. Estes Kefauver

    Estes Kefauver Junior Member

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    Hi Folks,
    2010 Prius, 105K. I've got a little seepage from the driver's side transaxle seal, at the inner end of the driveshaft.
    1. How common is this on Gen III cars? All the info I find about this problem seems to be from earlier models.
    2. How urgent is it to fix this? Will it spring a huge leak someday and run the transaxle dry? Or can it go on like that for years / tens of thousands of miles? Not that I'll wait THAT long, just want some idea of how serious this is.
    3. Are there any particular symptoms of low transaxle fluid on these cars that one should keep in mind?

    Thanks!
     
  2. JC91006

    JC91006 Senior Member

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    Good time to change out the seal and replace the transaxle fluid.

    I wouldn't wait too long on this, you'll need to fix it so sooner the better. A ruined transaxle can cost thousands.

    I did this on my gen2 last month, cost $10 for the seal and $30 for the fluid.
     
  3. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    It involves taking off brake rotor, wheel bearing hub, partial suspension disconnection? (n)

    I recently let pros deal with this, on a Civic. They quoted $135 all in but tax, which I thought was very reasonable. I even asked them to confirm, and yup yup.

    And then an hour after dropping it off I got the call: at least double, what can we say.

    I opted to go ballistic, and when I picked it up they'd swung embarrassingly the other direction: I think $98 WITH tax, lol.

    It's not for the casual DIY'r (me for example), you can come to grief just trying to remove the shock bolts.
     
  4. David Beale

    David Beale Senior Member

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    Keeping in mind the trans-axle is filled with a -lot- of oil, a little seepage is not a problem. Unless it causes some other problem, such as a fire hazard (not in this case). Or unless it is caused by a failed bearing. The level in the trans-axle is also easy to check and top up. -I- wouldn't worry about it.

    The word "seepage" means some oil and attracted dust on the housing around the seal, NOT a puddle on the floor/ground or oil sprayed around the chassis!
     
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  5. jerrymildred

    jerrymildred Senior Member

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    Assuming it's just oozing and not dripping, I'd schedule it for a convenient time. But don't confuse "convenient" with "when I get around to it." The latter can end up being a very long time and, as @JC91006 said, delaying too long will get very expensive. :eek:

    If it's dripping I'd get it done asap.

    As for it being easy to check, that's a matter of perspective and tools. If I had a hoist in my garage, I'd say it's easy. But I have a narrow one car garage and a sloping driveway. It would take me about an hour to check it by the time I made room, got it on jack stands, got the cover off, checked the level, maybe added to it, re-torqued the fill plug, and got everything buttoned up and put away again.
     
  6. JC91006

    JC91006 Senior Member

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    I bought a 2005 with a failed transaxle a couple years back, found out there was an axle seal leak. Not sure if that was a contributing cause to the transaxle failure though. Since you can't really check the fluid level, you won't know how low the fluid level is.
     
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  7. Estes Kefauver

    Estes Kefauver Junior Member

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    Thanks folks. I checked it out today. There's enough of a leak to be letting fluid wick down one of the seams in the transaxle housing, and there must be an occasional drip. Checked the fluid -- now, was I supposed to do that with it warm? It was not, (well, I think 85F ambient is warm enough to make it uncomfortable to work on the car, but maybe the transaxle was supposed to be at normal operating temp?) I'd estimate the fluid level was 1/2 inch below the fill hole (vehicle raised and approximately level). It makes me nervous enough that I'd not want to jump in and drive across the country, and since I never know when I might need to do that, I'll see if I can take care of it.
    I reviewed my owner's manual and found that there aren't any warning lights for trans too hot or the like. Does anyone know if any trans problems would throw a check engine light, or anything else? It just seems to me that when you can't easily check the trans fluid, because no dipstick, you should at least be able to rely on the vehicle's electronics to warn you if there's a problem.
     
  8. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    This was something I was wondering about: is the leak from a driveshaft seal, or a transaxle seam? I'm sensing it's the latter, which is actually not so bad.

    Considering it's taken it to 105K miles to drop this far, I would just repeat the exercise you did to check the level, with a quart bottle of Toyota ATF WS on hand, and maybe a fresh washer. Then, run a funnel with tube extension (about 3 feet, 5/8" OD or less) down from above, and add fluid till it starts flowing back out.

    Or better: get four quarts, two of the fill/drain bolt washers, and do a drain-and-fill. Even though it's not in the maintenance schedule, imho It's long overdue. The 4 quarts of fluid and washers will be about $40.

    Addendum: I don't think checking the level warm vs cold makes much difference. There's no mention in the repair manual instruction.
     
    #8 Mendel Leisk, Jun 18, 2017
    Last edited: Jun 18, 2017
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  9. Avi's Advanced Automotive

    Avi's Advanced Automotive Independent hybrid repair shop

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    I had a Gen 2 come to my shop for check engine light concern which turned out to be the catalytic converter. After fixing that and road testing the car, I went over the rest of the car. When I removed the fill cap to check the transmission fluid, I could see the fluid was BLACK! I didn't bother to check the level, but recommended a fluid replacement. She approved the replacement and I proceeded to remove the old fluid. When I removed the drain plug, approximately eight ounces of fluid came out. This car ran fine aside from a slight wheel bearing sound.

    To answer your question, there is no warning when you run out of transmission fluid.

    Posted via the PriusChat mobile app.
     
  10. JC91006

    JC91006 Senior Member

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    How were you able to see the fluid through the fill hole? Being black
     
  11. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    He says drain plug. Edited?
     
  12. m.wynn

    m.wynn Senior Member

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    This was once a common Gen 2 issue reported here but many years ago now. Maybe Toyota updated the seal in later Gen 2 years... That said, it's rare (at least rarely caught and reported) in Gen 3. My 2010 did weep from the driver side seal and I did the repair at 97k miles. It was never coming to a drip but it weeped enough that it was a dirty mess around the seal and down the side of the case. Similar in severity to the notorious timing chain cover "leak." It could have probably gone the life of the car with an oblivious owner but my OCD was having none of it.

    Anyway, it's an easy fix assuming reasonable DIY mechanical inclination. Get the steering knuckle off and pop the shaft out. I ended up positioning a pair of motorcycle tire irons at approximately 8:30 and 3:30 to get the shaft to pop out of the case. It did take some experimenting with the positioning before it finally popped out easily. But until you find that sweet spot, it can act like it's not going to come out. Just persist and you'll find the leverage points to where it pops out easily. Carefully remove the old seal with the method of your choosing with care not to scratch the bore. I fabbed a driver with a length of 2" PVC with a coupling on one end for a total length of 18". The end of the coupling got filed to perfectly fit the O.D. of the seal. I don't recall if the seal was flush in the bore or countersunk so note this on disassembly.

    DSCN2260.JPG DSCN2261.JPG DSCN2262.JPG trans seal invoice 001.jpg
     
  13. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    You're more'n likely correct that the leak is from a seal where drive shaft exits the transaxle, but OP's description is not that clear. His latest post had me thinking it's just a seal within the transaxle body, that's leaking. Maybe he's not sure either: stuff can leak and trickle around:


     
  14. Avi's Advanced Automotive

    Avi's Advanced Automotive Independent hybrid repair shop

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    There's usually a small amount of fluid in the drain plug.

    Posted via the PriusChat mobile app.
     
  15. JC91006

    JC91006 Senior Member

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    I changed out my 2005 recently with about 180k miles on it, fluid was also black and muddy looking. Also I noticed a lot of air in there when I opened up the drain plug.
     
  16. Estes Kefauver

    Estes Kefauver Junior Member

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    I am fairly certain that the leak is from the axle seal, there's far more oily dirt accumulated around the left side than the right. It's possible that there's additional seepage from the case seam, but I think there's a path for the fluid to run there from the seal. If there was a leak from the seam, would that require fixing, and what kind of job would it be? Thanks for the tool tip, @m.wynn , just last fall I had to create something like that to install a seal inside a Dana 60 front axle. @Mendel Leisk , do you interpret the manual's different sections 2 (add) and 3 (inspect) to mean on different occasions? Like you'd fill the trans, drive around a bit, and recheck? I saw a youtube video where a guy explains how to check the level on the Toyota transmissions that have the "straw"/drain plug, and temperature was a critical factor; I know these are much different, but I wondered if temp was still important.
    In general, I could probably live with a minor leak like this, just watch it over time to see how fast it is, but I'd feel pretty dumb if it suddenly got a lot worse and damaged the trans.
     
  17. JC91006

    JC91006 Senior Member

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    You can probably safely live with this leak, but I would top of the transaxle fluid now and then repeat every year.
     
  18. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    After the first transaxle fluid change I followed through: a day later put the car back up and checked level. It had not budged. So at subsequent fluid changes (I've done 3 in total) I didn't not bother with checking later.
     
  19. Estes Kefauver

    Estes Kefauver Junior Member

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    Well, I'm 1.5 hours into this, everything is going well, but I came back in to check the advice from @m.wynn about how to pry the cv axle out. I suppose once I try to pry at those locations, 8 and 3 o'clock, I'll answer my question about what I'm supposed to use as the fulcrum ... do you recall whether you work this from underneath or from the wheel well?
    It got me thinking, I should ask folks how long the CV axles last -- I'd consider getting a replacement now if it was a pretty sure bet it would only last another 20-40,000 miles (at 105K now), or if there's a chance I'll damage it as I try to extract it.
     
  20. David Beale

    David Beale Senior Member

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    I've never seen a post about a bad CV joint on a Prius. It must happen, just very rare.
     
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