Too much transmission fluid consequences?

Discussion in 'Gen 2 Prius Technical Discussion' started by brick, Jul 5, 2009.

  1. brick

    brick Active Member

    Joined:
    Dec 10, 2006
    1,083
    77
    0
    Location:
    Upstate NY
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    Would there be any adverse consequences from having a little extra fluid it the transaxle? I wasn't able to get the car completely level for my last change (only a few hundred miles ago) so I wound up draining it and putting in all 4 quarts of fluid, which came right up to the fill plug. But given the angle, I'm concerned that this is really a couple of millimeters above the max fill level.

    Given that this is more like a manual transmission than an automatic I can't think of a rational reason to be concerned. But I don't know everything. Thoughts?
     
  2. patsparks

    patsparks An Aussie perspective

    Joined:
    Jul 12, 2007
    10,664
    563
    0
    Location:
    Adelaide South Australia
    Vehicle:
    2004 Prius
    Model:
    N/A
    Wouldn't worry about it, mine is the same.
     
  3. jayman

    jayman Senior Member

    Joined:
    Oct 21, 2004
    13,439
    629
    0
    Location:
    Winnipeg Manitoba
    Vehicle:
    2004 Prius
    If it was an automatic transmission, you could have trouble. Since it's not, you would have to have it grossly overfull before you had an issue, eg seal leaks
     
  4. FireEngineer

    FireEngineer Active Member

    Joined:
    Oct 6, 2004
    1,247
    123
    0
    Location:
    SW-Side of Chicago, IL
    Vehicle:
    2010 Prius
    Model:
    IV
    Mine took a full 4 quarts and then was driven for 20,000 miles, half highway. No problems, no leaks, no MPG loss.

    Wayne
     
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,181
    6,283
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    4 US quarts is the capacity spec, and that is the amount that I fill.
     
  6. brick

    brick Active Member

    Joined:
    Dec 10, 2006
    1,083
    77
    0
    Location:
    Upstate NY
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    OK. Sounds like you guys are doing it the same way I did! Appreciate the feedback.
     
  7. David Beale

    David Beale Senior Member

    Joined:
    Jul 24, 2006
    5,963
    1,963
    0
    Location:
    Edmonton Alberta
    Vehicle:
    2012 Prius
    If you want to allay your fears, just remove the fill plug when you can find level ground to park on. Any excess will drain out.
     
  8. hc167

    hc167 Member

    Joined:
    Sep 21, 2007
    132
    19
    0
    Location:
    US
    Vehicle:
    2005 Prius
    I put little more than 3.5 quarts. Did I putting too little? I remember when I drained the old fuild, it was about 4 quarts. so I need to add more?
     
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,181
    6,283
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    Just to clarify, we are talking about transaxle fluid, not engine oil... :D

    When replacing transaxle fluid, you are supposed to have the vehicle level and add enough until the new fluid starts to seep out of the fill hole.

    The spec is 4 US quarts fill capacity. I have found that this spec is accurate. If your transaxle fluid is 0.5 quart low, I think it would be a good idea to add more fluid soon.

    It's not clear at what point insufficient fluid will result in damage. Considering that the cost of transaxle replacement is well into four digits, I don't see the point of taking unnecessary risks with that component.
     
  10. jayman

    jayman Senior Member

    Joined:
    Oct 21, 2004
    13,439
    629
    0
    Location:
    Winnipeg Manitoba
    Vehicle:
    2004 Prius
    For the CVT case, you want it up to the fill plug line. For the engine, 3.5 quarts of motor oil is plenty
     
  11. hc167

    hc167 Member

    Joined:
    Sep 21, 2007
    132
    19
    0
    Location:
    US
    Vehicle:
    2005 Prius
    yes, I am talking about transaxle fluid. Anyway, it was little under what the spec said. and it was changed last summer by myself and the car was on a level surface. and the drain hole drained some extra. that is how I know it was only little more than 3.5 quarts. maybe about 3.7 quarts. I will add the missing fluid in few days.

     
  12. hc167

    hc167 Member

    Joined:
    Sep 21, 2007
    132
    19
    0
    Location:
    US
    Vehicle:
    2005 Prius
    All of you confuse me now. from this site, Spring maintenance
    it stated clearly that "So 3.3 to 3.5 quarts seems about right for drain-n-refill, where the dry spec is a little over 4."
    If all you guy are drain-n-refill, how can you guys fill up with 4 quarts??:confused::confused::confused: I do not understand.


     
  13. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,181
    6,283
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    Hobbit's experience differs from ours. When you do the change, you can see for yourself how much fluid is needed so that the fluid level reaches the bottom of the fill hole.
     
  14. hc167

    hc167 Member

    Joined:
    Sep 21, 2007
    132
    19
    0
    Location:
    US
    Vehicle:
    2005 Prius
    why is Hobbit's experience differs from ours?? same car (second gen Prius). same CVT. so the capacity for holdong the fuild should be the same. The only thing that can be different is when you drain the fuild, you can completely drain out all the fuild, whereas, when I drain the fuild, there are still some portion of the fuild inside. I am not sure this will be the case.
     
  15. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,181
    6,283
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    The following is from Hobbit's website cited in your post #12 above:

    "One quart in, check underneath for leaks. Two more quarts in,
    and finally open up the level-check plug. Spec is 0 - 5 mm below the level
    of that hole; a little finger inserted and dipped *way* down could just barely
    find some fluid after three quarts. About a third of a quart later, it was
    almost to the lip, so I reinstalled the level plug and and added a splash or
    two more. So 3.3 to 3.5 quarts seems about right for drain-n-refill, where
    the dry spec is a little over 4."

    Note that Hobbit did not fill to the point where the fluid level was at the bottom of the fill hole. Rather the level was near the bottom.

    Perhaps he did not drain the old fluid to the same extent as other posters did. Perhaps there's production variability with the transaxles. In any event, as long as you have 4 US quarts of new fluid available and fill until you start to see new fluid coming out of the fill hole (or use up the 4 quarts), you'll be in good shape.
     
  16. brick

    brick Active Member

    Joined:
    Dec 10, 2006
    1,083
    77
    0
    Location:
    Upstate NY
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    I do think that how careful one is to drain the fluid makes a difference. The front end of the car was off the ground when I opened the drain plug and I waited until it was down to a few drips. To be thorough I lowered the car completely and another fraction of a quart drained out. (I wouldn't try this if you use ramps rather than a floor jack...probably not a great idea.) On the way back up I raised the driver's side first and still a bit more trickled out. So I suppose if someone drained the fluid without the front end raised, or worse with only the right-hand side of the car raised (which is all you really need for access), one could conceivably wind up adding substantially less than 4 quarts of new fluid and still read full at the fill plug.
     
  17. jayman

    jayman Senior Member

    Joined:
    Oct 21, 2004
    13,439
    629
    0
    Location:
    Winnipeg Manitoba
    Vehicle:
    2004 Prius
    The car may not have been perfectly level. May have been colder or warmer than when I used to change my fluid. Car itself may have been cold or hot, I did mine room temp

    Here in Canada, you can buy WS in a 4 litre tin can. I had made a ramp out of old railway ties at the hobby farm, and the ramp was perfectly level on top.

    With the Prius on top of the ramp, fluid drained, I'd refill by using a small pump until fluid started to ooze out the fill plug. I usually had about 150 ml left in the can
     
  18. DFWPrius2009

    DFWPrius2009 New Member

    Joined:
    Jul 12, 2009
    32
    1
    0
    Location:
    DFW
    Vehicle:
    2009 Prius
    Model:
    N/A
    I was told the CVT transaxle was a sealed system. No transmission fluid to ever change....
     
  19. ETP

    ETP 2021 Prime(Limit),Highlander HYB Plat,B52-D,G,F,H

    Joined:
    Apr 12, 2009
    2,764
    1,155
    0
    Location:
    Auburdale FL
    Vehicle:
    2021 Prius Prime
    Model:
    Limited

    welcome! That is the standard statement at the service department. However, most on this forum have discovered that the fluid is very dirty at 12K-35K and needs changed. There after it may not be as important and only time will tell.
     
  20. ETP

    ETP 2021 Prime(Limit),Highlander HYB Plat,B52-D,G,F,H

    Joined:
    Apr 12, 2009
    2,764
    1,155
    0
    Location:
    Auburdale FL
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    Also I was shopping at wal-mart today and read the back of the dextron 6 bottle and it said for WS and IV service. This stuff was less than half the price of the WS at the dealer that was not synthetic as far as I can tell.
     
Loading...