Changing Transmission Fluid, How To and Details

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by frisco_prius, Jul 6, 2019.

  1. frisco_prius

    frisco_prius New Member

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    Made this thread to ask some questions..
    But formatted/titled it in case it becomes an official trans fluid change forum sticky.

    As part of my 90k DIY service, I'm changing the trans fluid .. just need some more info before I start.

    Ive already watched the Nutz and Boltz DIY Youtube Video


    I already have:
    • New plug gaskets
    • Transfer fluid pump (for the oil)
    • Transmission Fluid ATF (5 quarts)
    • All the tools (sockets, brake fluid, oil pan, etc.)
    My questions are:
    1. Does the car need to leveled for draining or refilling the fluid? (angled on a leveled surface)
    2. Does the refill amount depend on whether car is hot or cold? (dealer representative said something about this)
    3. Do I just fill it till it starts leaking out or should I just fill it with the exact measurement that was given to me by the dealer for hot and cold. ( millimeters / quarts amount ) ..I forgot what that was but I have it written down somewhere.

     
  2. Rebound

    Rebound Senior Member

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    Yes, the car needs to be level. I’ve thought about this a lot, and here’s what I think:

    1) Use four identical jack stands on the four jack points.

    2) Use painter’s tape to tape a bubble level to your Driver’s door. If it’s on a level garage, then you level the bubble, and when the car’s raised, you can verify that it’s level.

    3) Once you’ve raised the car and removed the belly pan, remove the fill nut before you remove the drain nut. You can loosely replace it, but just be sure you can remove the fill nut before draining all that fluid. If, for any reason, you can’t remove the fill bolt, you’re in big trouble if you drain the transmission fluid.

    4) Yes, you fill until you can’t fill anymore... which will be when the fluid gets all over the place and makes a huge mess! Cause you’re just pumping, pumping, pumping... and all of the sudden, fluid shoots out of the thing and goes everywhere. Fun fun. As long as the vehicle is level, you won’t overfill it.

    5) You might want it to be a little warm when you drain, but not hot, and it should be fairly cool by the time you fill. I don’t think there is a temp spec for filling the fluid, but I assume it’s cold.

    Take your time pumping the fluid in. It’s very easy to spill.
     
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  3. frisco_prius

    frisco_prius New Member

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    Thanks, I don't even have a nice car jack or jack stands ..I usually just put it on ramps.

    BTW , If the overflow is unpredictable like you say .. how will know if I've overfilled ?
     
  4. Rebound

    Rebound Senior Member

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    You shouldn’t do this with only ramps. If you were local, we could do this in my garage, or if you’re in the SF area, you could do it at a meetup there. But don’t do this with just ramps, because it won’t drain or refill correctly.

    It’s very simple: There’s a drain bolt at the bottom of the transmission. But if the car is tilted, the fluid won’t all drain out. The fill bolt is on the side of the transmission. So you drain, put the drain bolt back, open the fill bolt. You put oil into the fill hole until it’s full... which means it’s full when some fluid comes out of the fill hole. But if the vehicle isn’t level, there’s no way to know if you’ve over or under-filled the transmission, so... DON’T do that. Better to leave as-is.
     
  5. jerrymildred

    jerrymildred Senior Member

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    If your floor is level and your ramps are all the same, then the car should be level, but I don't think that ramps high enough to help you would fit under the car. In fact, I got rid of my ramps because the bumper hit the ramp before the front tire. I recommend getting a decent floor jack and stands.

    I don't use a pump. It's very easy to snake a properly sized clear tube down from above and pour the fluid into a funnel into the tube. When you get close to the amount required, just pour in a little at a time and keep checking for fluid coming out of the top hole into your drain pan.
     
  6. jb in NE

    jb in NE Senior Member

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    Drain the fluid into a container and measure it. Then put the same amount back in.
     
  7. Rebound

    Rebound Senior Member

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    That’s not the correct procedure. You’re supposed to fill it to the bottom of the fill hole, with the car level.
     
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  8. Rebound

    Rebound Senior Member

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    I did one change with a pump and one change using a funnel and tube.

    Two problems with the funnel/tube approach: First, it takes two people or a lot of patience. Second, when the fluid is full, the fluid will leak out of the transmission. At the same time, the tube, and maybe the funnel, is still full of fluid.

    With the pump method, you have better control over things spilling. I like the way NutzAboutBolts shows it, by putting all the bottles into a large drain basin.
     
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  9. jerrymildred

    jerrymildred Senior Member

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    To each his own. I did three with the funnel and tube and thought they were very easy except for the hassle of the undercarriage splash shield removal and replacement on my PiP. That was the only part that tried my limited patience. ;) Now I'm about to get to try that on the Prime. Just got the oil the other day. The book says it takes 3.9 quarts. When I get to 3.5, I just put in about 0.1 or 0.2 at a time and check for overflow. Usually, I hear it splash into the pan right away.
     
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  10. jb in NE

    jb in NE Senior Member

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    But if the car is not level (i.e on ramps), this will get the level back where it was. Not the preferred method, but if you aren't level it works.
     
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  11. Mendel Leisk

    Mendel Leisk Titanic Social Director

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    Not necessarily: the fill hole is towards the back of the transaxle. If the car's front is up on ramps, it'll be impossible to push the same amount back in: it'll start draining back out too soon, due to the tilted transaxle.

    Also, there's the presumption the level was correct to begin with. It likely was, and yeah I always do check drained fluid (have a graduated drain vessel), but I'm not going to base how much new fluid I add based on that. Especially with the foolproof fill-while-level method available.

    I would use a funnel with 3 foot hose extension, max hose diameter around 5/8" (so it'll fit). Yeah you can use a transfer pump, but funnel/hose is dead simple. Run it down from above, best to have an assistant pouring.

    Probably you'll be ok with about 3.5 quarts. Maybe you can return the 5th if it's not cracked?

    The simple and foolproof method to get the level right is to fill, with the car level, till it starts coming back out. The simplest way to get there, in your shoes, would be to run the front up on ramps, jack up the back, at the rear/central jacking point, with a half-decent floor jack, and put a couple of safety stands in there. It doesn't have to be machine shop level, but do the best you can.

    I just use a floor jack and safety stands front and rear, but whatever you're comfortable with. One thing, I like to put a large block of tree trunk (loosely) under a main cross beam, whenever I'm crawling under, something thicker than me. A failsafe.

    Also, I do not use the scissor jack locations for safety stands, prefer nearby, more substantial structural points. If you're interested I can post a pic.

    Do you have a torque wrench (drain and fill bolts are 29 ft/lb), and a 10 hex allen-key style "socket"? Also, a long handled wrench (sometimes referred to as a breaker bar) is good. While the drain and fill bolt torque isn't that high, it's a bit of a fight to break them loose. I'd recommend to take the whole engine underpanel off too.
     
    #11 Mendel Leisk, Jul 7, 2019
    Last edited: Jul 7, 2019
  12. CR94

    CR94 Senior Member

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    I dealt with the leveling issue relatively simply by doing it on a moderate hill, with rear wheels up the hill and front on ramps.
    Fortunately, the quantity of oil is not super-critical, as long as you get into the right ballpark. I ended up filling about 0.2 quarts more than I drained.
     
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  13. jerrymildred

    jerrymildred Senior Member

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    Similar here. My driveway slopes, so the car is nearly level when the front is on the stands.
     
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