Transmission Fluid change

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by ATHiker, Nov 29, 2017.

  1. ATHiker

    ATHiker Senior Member

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    I am sure everyone has an opinion on when to change your transmission fluid.

    Don’t care (actually I do, but plenty of other threads on this for previous generations).

    My question is why Toyota may have arrived at theirs.

    If I am reading my owner’s manual correctly, they do not recommend changing it before 120,000 miles — and even then only if you operate under special conditions (towing, roof top carrier),

    Any ideas on why Toyota is not suggesting we change it sooner?
     
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  2. alanclarkeau

    alanclarkeau Senior Member

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    Guess - oil life is much longer than it used to be due to better oils, and guess again - because, unlike a normal Manual Transmission, there aren't the extreme pressures between gears etc.

    Cynical answer - they want to:
    1) keep the apparent cost of maintenance appear low; and
    2) because they really aren't that concerned beyond Warranty End - as it becomes a User Pays repair - or, better for them, a new car. I reckon that, because the relative cost of new cars has decreased so much in the last 20-30 years, it is only a rare customer who is looking to keep them for a long time. For instance, my new 1995 Manual Mazda 323/Familia cost about $22,000 - in 2017. Today, I can buy an equivalent car which has heaps more standard equipment, Auto, Cruise, safety equipment and a 5 or 7 year warranty - still for $22.000.- which is the equivalent of more like $36,000 - so it's effectively much more affordable.
     
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  3. tpenny67

    tpenny67 Active Member

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    My understanding is that cars are designed with a "target lifetime" in mind, for example, 12 years, 150,000 miles (note: numbers picked out of thin air for the purpose of example). This sets the standard that all parts are expected to meet, so that they don't waste money over designing one part and under designing another. Also, if you expect the car to average 30mph over its life, that translates into 5000 hours of operation to reach 150k miles. So how long do the LEDs in the tailights need to last? How about the displays in the instrument cluster? Answer: 5000 hours. How long does the fuel pump need to last? 5000 hours. The wheel bearings? 150k miles. Etc, etc.

    So, will the transmission last the target design life without a fluid change? If the answer is yes, then no change is recommended by the manufacturer. Will it last longer if you change the fluid? Probably. Will the car as a whole last longer? Maybe, maybe not, depending on whether your driving fits the predicted 150k miles in 12 years at 30 mph.

    A properly designed car should meet it's (undocumented) target life with few problems if you follow the recommended maintenance. A few unlucky cars will develop problems before then. A lucky few will go far beyond the design life. A large number will probably have some combination of rust, sun damage, accident damage (if not outright totalled), stolen, vandalized, road rash, rodent infestation, dog puked in back seat, and generally have been reduced to ratty old cars around the time they reach their targetted lifetime.
     
  4. bisco

    bisco cookie crumbler

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    does anyone look at the maintenance requirements before purchasing?
     
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  5. Mendel Leisk

    Mendel Leisk Sand Pounder

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    And how about the "acceptable" oil consumption, that little gem embedded in the Toyota Owner's Manuals.
     
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  6. ATHiker

    ATHiker Senior Member

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    Since I am at 60k miles now and consider that just a brief start to a long relationship, I kind of want to change it.

    That said, I really don’t trust my dealer — or myself — not to do more harm than good if a change is not required. Primum non nocere (I had to google that up, but it fits).

    The whole idea of “target lifetime” is something I never considered, however. That concept might inspire me to get that done at my next service.
     
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  7. Fester

    Fester Active Member

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    My dealer is going to consider me a bit OCD because I'm going to have them do a drain and refill on the transaxle fluid at the first scheduled "free" oil change. Technically, its to remove bits of wear-in particles from the fluid. Probably have it done once more at the second oil change too to remove particulates that are left over. Engine and transmission systems are a lot more refined now, but still the "high points" on the wear surfaces do get removed and end up in the fluid. There is a magnet in there to latch on to the steel bits, but none for anything else, and after viewing a teardown of the transaxle, theres a whole lot of complex passages that fluid has to go thru. At this point in life probably me last roundup in the new car department. So I figured a little OCD might go a long way:)
     
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  8. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Ok, since you're going off-topic, the topic being why Toyota has this policy, I feel entitled to jump in:

    From what I've seen in the 3 transaxle fluid changes I've done so far, in a span of around 60K kms, I'd say the most opportune/effective time for this would be the one year mark, say around 10~15K miles. No point in sitting in that "stale bath water" for any longer, certainly not years.
     
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  9. David E. Edwards

    David E. Edwards Junior Member

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    One reason auto makers are going to longer drain periods is the EPA uses that data
    in determining the expected mileage. They use a total petroleum use, so the longer
    they suggest on drain times the better the mpg will be.
     
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  10. frodoz737

    frodoz737 Top Wrench

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    With the combination of better vehicle reliability and fluids (think back to the 70's), the guise of low maintenance costs and "Free Maintenance for Two Years" has pushed things to the limit for long haul owners. They did not recommend brake fluid exchange until recently either. THERE ARE NO SUCH THING AS LIFETIME FLUIDS for our vehicles. As previously stated, they use a best average.

    Oil/Filter - first at 1,000 miles then every 5,000 miles with Toyota 0W-20.
    Transmission - first at 1,000 miles then every 20,000 after with Toyota WS.
    Brakes - every 20,000 miles with Toyota DOT-3 (don't mix brake fluids).
    Both engine coolants - every 50,000 miles or every 3 years with Toyota Coolant.

    As always on car forums, others will disagree, but that's OK. My recommended fluid changes are more real world than the gas-n-go generation's...but then...I turn a wrench for a living. I don't like making expensive preventable repairs and I don't like buying new cars every 5 years. The Prius line is very reliable, but it does not run on magic. ;)

    $150 for a transmission drain and fill is fair price (unless you do it yourself) and will give you the peace of mind you want/need.
     
  11. Mendel Leisk

    Mendel Leisk Sand Pounder

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    I'm not sure I believe that. It's a good concept, but isn't mpg just mpg?
     
  12. Elektroingenieur

    Elektroingenieur Senior Member

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    I skimmed through 40 CFR Part 600 and didn’t notice anything that suggests that the EPA fuel economy or CO₂ emissions estimates take into account the use or replacement of operating fluids other than fuel, but I claim no special expertise in this area.

    I don’t mean to imply that the environmental impact of servicing should be ignored, but any regulation would have to avoid creating perverse incentives: if fluid drain intervals were increased too much, service life would be reduced, and more vehicles would have to be made, with all that implies.
     
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  13. tpenny67

    tpenny67 Active Member

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    A Prius transaxle is not much different than a standard transmission or a normal differential on a rear wheel drive car/truck. They're all gears in a box without any clutches or other friction elements (unlike automatic transmissions, CVT, and limit slip differentials). My piece of mind comes from having had them last for 20 years and over 150k miles on the original fluid.

    Perhaps the Prius isn't designed to the same quality standards as Ford or Chevy </sarcasm> :)
     
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  14. frodoz737

    frodoz737 Top Wrench

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    Considering I drive 2 Prii and a RAV4 HV, save the sarcasm for someone applicable. Do yourself a favor and have the transmission fluid changed on your 2014. Collect, view and have a sample analyzed...you may change you mind. Regardless, it's your car, your money, your time and your choice. Enjoy.
     
    #14 frodoz737, Dec 1, 2017
    Last edited: Dec 1, 2017
  15. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Whole hearted agreement with the need to change: it is simple and cheap, no need to invest debate in this, just do it. I wouldn't bother with sample analysis, though.

    Toyota Australia at least, shows transaxle fluid change for 4th gen Prius, in the extreme service guideline. Is that a first?? Full booklet here:

    http://toyotamanuals.com.au/docs/prius-50-series-warranty-service-booklet-nov-15-current/

    Screen grabs:

    upload_2017-12-1_13-35-28.png

    upload_2017-12-1_13-35-0.png
     
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  16. Mendel Leisk

    Mendel Leisk Sand Pounder

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    I got tired at looking at the Aus. Schedule with my neck cranked, and jumping page, cobbled it together rotated and on one page.

    upload_2017-12-1_22-7-11.png
     

    Attached Files:

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  17. tpenny67

    tpenny67 Active Member

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    Sorry, did not mean to offend, merely trying to point out that I don't see why Toyotas need to be maintained differently than any other car brand, with my tongue in my cheek of course. I generally follow manufacturer maintenance recommendations, and it's worked for me for 30+ years of driving.

    Perhaps that's what we're really talking about here. We're both doing what has historically worked for us, and how dare we poke holes in that by presenting evidence to the contrary?
     
  18. SagradaFamilia

    SagradaFamilia Junior Member

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    G'Day,
    Some details regarding the replacement of the transmission fluid (P610 Transaxle) in my 2018, GEN4, Prius. (20900 mi) To be clear, the information provided in Prius-chat has been more than valuable in guiding my modest efforts. Thanks to all!

    * The drained fluid was still a translucent raspberry color but slightly darker than new.

    * I don’t think the drain plug is magnetic but there was no attached wear products or apparent residue.

    * Replacement was 4 new quarts of Genuine Toyota ATF WS. The manual calls for 3.8 quarts and some is trapped in the hand pump but the bottles were largely empty. The back-flow out the fill hole convinced me it was at capacity. Yes, that’s a messy cleanup as it gets behind flanges on the casting.

    * To level the vehicle, I had the front wheels on ramps and then used a floor jack under the rear lift point…backed up by jack-stands. A level can be used against the flat bottom face, under the running board beneath the door, to check vehicle horizontal.

    * The part number for the drain and refill plug gaskets is 90430-A0003. (Photo below) These are solid aluminum rings and not a compression ring like on spark plugs. I believe the torque spec on these P610 Transaxles is 37 Ft-Lbs, but you may wish to verify this with your dealer. As per previous advice, the refill plug was broken free first with a 10mm Allen socket on a 3/8” drive, 12” ratchet. It was not too difficult.

    * The part number for the reusable clips that support the bottom-cover (or air-dam) under the engine is 90467-07220. (The first broke as I attempted to pop out the center with a flat blade screwdriver. Even with more care, another broke as well. Just under $2 each at Toyota.) I only needed to remove the oil replacement cover and the large bottom-cover. There are four 10mm hex-head bolts that simultaneously secure the foremost bottom cover that need to be removed, but the forward cover is not actually taken off. During reinstallation slide front edge of the large bottom-cover into place beneath the front cover before using any clips or bolts or there will be rework.

    * Yes, it can be very messy. Cardboard on the floor and many paper towels.

    * The hand-pump was purchased on-line specifically for this effort, $12. The ½” source, and discharge hoses were trimmed to make handling easier while under the vehicle.

    *The locations of the drain and refill holes are not in the same locations as on GEN3. Look for the 10mm hexagonal sockets. (Photo below)

    View is from the passenger side looking to left, slightly aft. Notice the vehicle's front-left wheel at the bottom.
    The Drain is on the transaxle bottom as shown on the right in the photos. Refill is higher, toward the aft of the transaxle.
    upload_2019-10-22_23-37-54.png

    Another view with better illumination.
    upload_2019-10-22_23-39-13.png

    Example gasket washer....aluminum.
    upload_2019-10-22_23-23-28.png

    Did I mention that it was messy? :)
     
  19. Ajrob671

    Ajrob671 Junior Member

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    Thanks for the this information
     
  20. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Very good description, thanks.
     
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