How to Change Your Transmission Fluid

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Triparadox, Aug 4, 2019.

  1. Triparadox

    Triparadox Member

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    I'm thinking of bringing it out to a local mechanic to have it changed since I'm going to need a pump and some hose just to be able to fill it from under the car. I also don't think I have the power to unscrew that bolts if they're so tight (which is most likely since it's connected to transmission chamber). Do you think it's OK to just let a mechanic do the job? Also the more I watch about DIY-ing your car, the more my doubt come to those mechanics: Will they really change it since Prius is technically advertised as 'No need for changing'. Also do I need to bring my own fluid?
     
  2. schmuber

    schmuber Member

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    Guns and roses Pump and hoses are $10 or less, what's the problem?… And if you can't unscrew the bolt, get a ratchet with telescoping handle. Better yet, get a set of breaker bars. Heck, throw an electric impact wrench into the mix, and all of it still will be cheaper than getting your TF changed (maybe) by a mechanic.
     
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  3. jerrymildred

    jerrymildred Senior Member

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    You don't even need a pump. I use a 3' piece of clear tubing and a funnel. And there is a torque spec for those plugs. I don't have it handy, bit it's not that tight. I used a half inch breaker bar and it was easy on all three cars that I've done. Be sure to remove the fill plug first just in case you do have a problem.
     
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  4. ASRDogman

    ASRDogman Senior Member

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    Any "lifetime" fluid means lifetime of the warranty in the manufactures eyes.
    In theory, sealed hubs should never wear out. They are sealed so the grease can't get out or dirt in.
    But heat, and wear and tear break the grease down. Same for the transmission fluid.
    It REALLY is easy to change. The hardest part will be getting the car high enough and level so you can get under it
    to be able make sure you have the correct amount of fluid. About 3 and 3/4 quarts.
    You will need a longer breaker bar, or a pipe on the end of it for leverage to break it free.
    It would be a good idea to watch several video of what you want to do because you will not only become more familiar
    with it, but also see some shortcuts or easier ways of doing the job.
     
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  5. Raytheeagle

    Raytheeagle Senior Member

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    27 foot pounds(y).
     
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  6. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    Close, spec is 29:

    upload_2019-8-4_7-20-16.png

    I'd second that. And make it a funnel and hose DEDICATED for Prius transaxle fluid change, avoid contamination, albeit slight.

    Again, second that. I use a long handled (roughly 18") 1/2" drive ratcheting wrench, with a swivel head, makes it easy. Also need a 1/2" to 3/8" adapter, an extension is handy, and the drain bolts are socket-head cap screw requiring a 10mm Allen Key style (male) "10mm hexagon socket wrench". Stanley for one sells a set. Visual aid:

    upload_2019-8-4_7-42-23.png

    ^ This is one time I prefer Honda. They use a similar socket-head cap screw, but with a 10mm SQUARE hole, meaning any 3/8" ratchet wrench or extension works, with nothing extra.

    Use Toyota ATF WS fluid. Toyota is quite adamant about this in the Owner's Manual. Besides the (attached) Repair Manual instruction, I've got another document that recommends to only use fluid from newly opened bottles; don't store leftovers for next time. 4 Quarts or Liters should be enough.

    Also get replacement washers, just to play it safe. A lot of people here ask about part numbers, insist on buying sight-unseen on Amazon. I would recomend Toyota dealership part department, for both the fluid and the washers. Just tell them your vehicle model/year and you need transaxle fill/drain bolt washers.

    You also need some (safe) method to have the car raised AND level, since the method for getting the level right is basically to fill till it starts coming back out (with the car level).

    The (attached) Repair Manual instruction says to recheck the level after a test drive. That's not trivial, and I did do that the first time, found absolutely no change in the level, would not bother with that.
     
    #6 Mendel Leisk, Aug 4, 2019
    Last edited: Aug 4, 2019
  7. Montgomery

    Montgomery Senior Member

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    3' of clear tubing and a funnel.............................seems I have heard these items used in some type of physical "cleansing" procedures........................
     
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  8. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    Just be sure to clean it out after...
     
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  9. Montgomery

    Montgomery Senior Member

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    LOL
     
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  10. Raytheeagle

    Raytheeagle Senior Member

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    :eek:
     
  11. Rebound

    Rebound Senior Member

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    There’s no flush when changing Prius transmission oil, it’s just drain and refill.

    Unless you were confusing transmission oil change with something else, in which case, you need to hire professionals. Several, in fact.
     
  12. Montgomery

    Montgomery Senior Member

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    LoL, I hope you all are taking my comment in fun. Seems lately a lot of us have been getting attacked with aggresive responses. I'm trying to "lighten up" the atmosphere. All in fun.
     
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  13. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    I think a lot of people just use the term flush, although I agree, it's misleading. I think dealerships in particular promote the term, it sounds more impressive. :rolleyes:
     
  14. ASRDogman

    ASRDogman Senior Member

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    I would stay away from impact wrenches for these. Unless you can find a 10mm impact allen.
    You risk damaging the bolts and possibly the case.
    If you measure what you drain, you'll have a good idea what goes back in.
     
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  15. schmuber

    schmuber Member

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    Most of the 1/2" impacts are indeed too powerful for this job.
    However, 3/8" impacts (such as Ryobi One) are pretty harmless yet very useful for stuck bolts&nuts.
    No different than gently tapping a regular box wrench with small mallet.
     
  16. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    No harm in loosening with an impact? Still, if it's torqued to 29 ft/lbs, it's trivial to break loose with 18" or longer handled wrench. Even for a Bantam weight like me lol.

    It's when the previous maintainer tightened it with an impact that the fun starts.
     
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  17. schmuber

    schmuber Member

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    When I had my last set of tires installed, the shop used an impact so enthusiastically that I broke a 24" breaker bar (!) trying to undo the lug nuts.
     
  18. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    Give 'em an appropriate Yelp review.

    It's good to stand outside and watch how they wrap up some other customer's job, if you have the time. Good places you'll see a last guy go around with a torque wrench. Hopefully not just going through the motions though.
     
  19. Rebound

    Rebound Senior Member

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    With traditional automatic transmissions with torque converters, you cannot drain and refill the transmission fluid, because there’s a transmission oil pump and cooler, and myriad galleys that the oil flows through. So if you just drain, even by removing the whole transmission pan, only half the oil comes out. So you have to remove the transmission oil lines and flush new fluid through it. This is quite expensive, but it is the traditional way of changing the oil in an auto transmission.

    When a dealer says he’s going to flush the oil in your Prius transmission, it most likely means he’s going to sell a $300-$350 transmission flush service for a transmission which doesn’t need one. In fact, not only does the Prius transmission not need a flush — it CAN’T be flushed! There is no transmission cooler and no lines to attach a flush machine to.
     
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  20. ASRDogman

    ASRDogman Senior Member

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    I got paid extra when people used impacts! Because half the time they didn't use the impact socket!
    Just use the CORRECT tool for the job.
    But, as always it's YOUR car, do whatever you want with it.
     
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