1. Attachments are working again! Check out this thread for more details and to report any other bugs.

2005 Prius transmission starting to slip after hard mountain road climb

Discussion in 'Gen 2 Prius Technical Discussion' started by Dave Shrader, Aug 18, 2016.

  1. Dave Shrader

    Dave Shrader New Member

    Joined:
    Aug 18, 2016
    4
    2
    0
    Location:
    Mt. Pleasant
    Vehicle:
    2005 Prius
    Model:
    N/A
    2005 Prius transmission starting to slip after hard mountain road climb? Just started to do this. Is there a transmission dip or check capability?
     
  2. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

    Joined:
    Feb 14, 2010
    6,035
    3,854
    0
    Location:
    Rocky Mountains
    Vehicle:
    2006 Prius
    Model:
    Three
    There is no transmission. There is nothing to slip. It is a single statically geared planetary drive system.

    If you mean you had "loss of power" then that is pretty normal when the battery is low and in the mountains. Tell us what happened, not what you think is wrong as your basic understanding of the vehicle is incorrect.
     
    edthefox5 and strawbrad like this.
  3. JimboPalmer

    JimboPalmer Tsar of all the Rushers

    Joined:
    Apr 14, 2009
    12,470
    6,862
    2
    Location:
    Greenwood MS USA
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    The transaxle has a drain hole and a fill hole, you check the level by sticking a finger in the fill hole.
     
  4. Dave Shrader

    Dave Shrader New Member

    Joined:
    Aug 18, 2016
    4
    2
    0
    Location:
    Mt. Pleasant
    Vehicle:
    2005 Prius
    Model:
    N/A
    Please describe Exactly where is the fill hole sooI can find it?
     
  5. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

    Joined:
    Feb 14, 2010
    6,035
    3,854
    0
    Location:
    Rocky Mountains
    Vehicle:
    2006 Prius
    Model:
    Three
    Again you might want to explain what is actually happening as an ATF change doesn't do much in the Prius. But the hole and bolt is close to the middle in the vertical dimension of the transaxle. The procedure is NOT a flush, it is a simple drain and fill.

    You have lots of people on this site that know the car intimately. What you describe is not physically possible on a Prius.
     
    strawbrad likes this.
  6. JimboPalmer

    JimboPalmer Tsar of all the Rushers

    Joined:
    Apr 14, 2009
    12,470
    6,862
    2
    Location:
    Greenwood MS USA
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    I think you are off base, but here is the answer you failed to google.
    This nice man has detailed instructions on how to do a ATF change. Toyota Prius: How to Change the Transmission/Transaxle Fluid - PriusDIY.com

    This may be the single clearest photo (by hobbit)
    [​IMG]
    (the upper plug is fill, the lower plug is drain. Always open fill first, you would hate to have drained the fluid only to discover you could not fill it back)
     
  7. cwerdna

    cwerdna Senior Member

    Joined:
    Sep 4, 2005
    12,544
    2,122
    1
    Location:
    SF Bay Area, CA
    Vehicle:
    2006 Prius
    +1

    If the "loss of power" is accompanied by high engine RPMs (that is very audible) while climbing mountains when the HV battery runs low, it is NOT transmission slippage.
     
    strawbrad likes this.
  8. Dave Shrader

    Dave Shrader New Member

    Joined:
    Aug 18, 2016
    4
    2
    0
    Location:
    Mt. Pleasant
    Vehicle:
    2005 Prius
    Model:
    N/A
    OK, here is the best description of what I am experiencing.

    After traveling around 16 miles of constant climbing from 2,500' to 4,000' elevation on highway 105 from Boone, NC to Tynecastle, NC and the Prius engine has been whining loud as it usually does in that situation or when in the "B" position going down hill and the speed gets up to 45-50 MPH. I use the "B" position to help going down hill to save brake wear and heating up.

    The feel I get is that the forward momentum seems to falter and then catch hold and then falter again and then catch hold until I get to a more level ground or let off the accelerator. That is the best I can describe it. I did check the engine oil level after letting the engine cool off and it was normal level.

    I hope this helps you understand what is happening. I am just concerned that it is hurting something in the propulsion unit of the Prius and don't want to continue without seeing a dealer to make sure I am not damaging something.

    By the way, I have 248,000 miles on this 2005 Prius and I am the original owner and LOVE THE CAR!!!

    Thanks to all for your help with this.
    Dave Shrader
     
    Shane Burns likes this.
  9. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,073
    14,980
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    There is ATF in a Prius transaxle, but it's only there for lubrication and cooling, it doesn't deliver any power or work any bands or clutches (there aren't any) the way it does in a conventional auto transmission. That's why there's no dipstick, and they don't make a big deal about the drain and fill plugs, and if you check you'll find it's all there (unless you have a leak), and changing it doesn't hurt, but won't have anything to do with what you're experiencing.

    In a Prius transaxle, the electrical power path is an absolutely essential part of how power gets from the engine to the wheels. It can be cut back either when the battery reaches an extreme state of charge or temperature, or when the inverter circuitry gets too hot. All of those things can happen in mountain driving. When that happens, you feel like the engine is over-revving and not enough power is getting through, which is the same way a slipping auto transmission feels, so that's probably what you've experienced.

    Bear in mind that all of this is under control of the car's computers, which are monitoring the inverter, transaxle, and battery temperatures, and battery state of charge, all the time. When you feel a cut-back, it does mean you're pushing the car hard, but it doesn't mean you're breaking anything, it just means the computers are saying "ok, enough of that" before you break anything. (The first-generation Prius dash had a 'turtle' light that could come on then, but I think they did away with it later.)

    Probably the most useful thing you can do here is to get something like the Torque app (or a ScanGauge II from the PriusChat shop), and set it up so you can see what's happening with your battery state of charge and your various temperatures while driving. It won't change what the car is doing, but will help you understand why, when it does.

    -Chap
     
  10. Dave Shrader

    Dave Shrader New Member

    Joined:
    Aug 18, 2016
    4
    2
    0
    Location:
    Mt. Pleasant
    Vehicle:
    2005 Prius
    Model:
    N/A
    Thank you very much - I feel better and I believe I will pursue the Torque app. Does it work on an IPhone 6S+ or android? I will also investigate the ScanGauge II as well.
    Again Thanks for the detailed information to a PRIUS Lover (I have two - 2005 (248,000 miles) and 2013 Persona (15,000 miles).
    Dave
     
    Shane Burns likes this.
  11. JimboPalmer

    JimboPalmer Tsar of all the Rushers

    Joined:
    Apr 14, 2009
    12,470
    6,862
    2
    Location:
    Greenwood MS USA
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    If you can stand his academic tone of voice, this is a good explanation of how the transaxle works mechanically. (there is a lot of software to make that work seamlessly.

     
    Shane Burns likes this.
  12. cwerdna

    cwerdna Senior Member

    Joined:
    Sep 4, 2005
    12,544
    2,122
    1
    Location:
    SF Bay Area, CA
    Vehicle:
    2006 Prius
    Loud whining up hill is normal, esp. when the HV battery is depleted. Check the energy monitor screen.

    It's also normal going downhill in D or B if the battery is full. I pointed this out when in D in my post at Engine RPM is high, car is not accelerating | PriusChat when I lived in an area w/a not that long-downhill grade. It's normal, apparently to prevent the battery from getting overcharged.

    I've also encountered this in my (not often at all anymore) drives between here and LA in the downhill portions.

    Also see my links at Engine over-reving in Cruise Control | PriusChat.
    Possibly normal, due to the above.
     
  13. edthefox5

    edthefox5 Senior Member

    Joined:
    Jul 25, 2007
    10,096
    4,795
    0
    Location:
    Clearwater, Florida
    Vehicle:
    2007 Prius
    Model:
    Two
    Be aware that's the most stress you'll ever put on a Prius the low volt hi load scenario. This is how you kill the trans. And its the Inverter thats whinning. The engine is screaming because the hybrid battery is flagged and the engine is desperately trying to produce all the power your still demanding out of it by pushing the go pedal. Many a Prius has ended up on the side of the road doing this. The Inverter coolant was probably bubbling it was so hot and so was the trans.
    Its not a magic machine. Power has to come from somewhere. Next time watch the battery level. When it goes purple pull over and give it a rest and open the hood and see how hot its getting. Feel the Inverter cover. Then force charge the battery by pushing the accelerator pedal and standing on the brake till you regain some blue bars.

    Hope you have good trans fluid in it because you gave it quite a beating..
     
  14. Kate M

    Kate M Junior Member

    Joined:
    May 18, 2019
    64
    14
    1
    Location:
    California
    Vehicle:
    2005 Prius
    Model:
    One
    Hello, I’m new. Reading this post as I’m trying to diagnose symptoms on my 2005 Prius with 118k miles.
    Having similar issues as described above. Watched the transaxle explanation video. Helped a bit.

    I don’t know the terminology, but it feels like MG1 and MG2 are having sync issues? High rev as I merge into freeway speed. And same (?) rev sound as I’m idling at a stop light. It’s random and not often, maybe 3-4 events in the last 2 weeks.

    Have never had an issue before this. Replaced the auxiliary battery (the expensive one) around 80k miles.

    Love my Prius. Any thoughts or suggestions?

    Thanks Kate
     
  15. Kate M

    Kate M Junior Member

    Joined:
    May 18, 2019
    64
    14
    1
    Location:
    California
    Vehicle:
    2005 Prius
    Model:
    One
    Oh, just learned it was NOT the expensive battery I’ve replaced. Sorry for my ignorance.
     
  16. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    found it.

    you are probably experiencing a weakening hybrid battery. without any dash trouble lights, it is hard to know for sure.
    are your mpg's okay? are there any wild swings in the battery gauge?
     
    Skibob likes this.
  17. Kate M

    Kate M Junior Member

    Joined:
    May 18, 2019
    64
    14
    1
    Location:
    California
    Vehicle:
    2005 Prius
    Model:
    One
    Hello, I need to start monitoring the energy use screen—as everyone says. Not sure what to watch for.
    Thanks
     
  18. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    not sure about the energy use screen, i would ask whoever posted that.

    i would watch the battery icon for large, fast up and down fluctuations.

    a good battery will stay around 5-6 bars most of the time, with occasional all green and two purple. but a week cell charges and discharges quickly, making the gauge go quickly to full, then to zero, and so on.
     
    Kate M likes this.
  19. Kate M

    Kate M Junior Member

    Joined:
    May 18, 2019
    64
    14
    1
    Location:
    California
    Vehicle:
    2005 Prius
    Model:
    One
    Okay...priceless help here...I’ll watch that...thanks!
     
    bisco likes this.
  20. Kate M

    Kate M Junior Member

    Joined:
    May 18, 2019
    64
    14
    1
    Location:
    California
    Vehicle:
    2005 Prius
    Model:
    One
    Re MPG, I’ll start keeping track. Thanks.
     
    bisco likes this.