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Transaxle replacement: how to/DIY writeup?

Discussion in 'Gen 2 Prius Technical Discussion' started by Lavalamp, Feb 14, 2013.

  1. Lavalamp

    Lavalamp Junior Member

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    I have a 2005 Prius with right under 95k miles. Recently on the last 2 hour leg of a 9 hour road trip the CEL (red triangle) came on, along with the yellow brake and VSC lights; cruise control stopped working as well. I could stop and cycle the car on/off a few times to clear all the lights and the car would drive fine for another 20 minutes, then the lights would come back. After a couple times I kept driving with the lights on to see how far it could go, eventually the ICE shut off and I was basically in EV mode. I stopped, reset the lights and kept driving some more. This time after the lights came back and the ICE shut off, a temperature icon came on the MID.
    I decided to stop for a little bit and let the car cool off, then I went on my way again and decided to keep the car at 55mph (instead of the 75mph I was doing). It was 40F outside so I figured if I keep the speed low enough the ambient air should keep it cool enough. It worked and was able to get home without any more errors.
    It's been about 3 weeks now and I've been driving around town without any issues, except for a howling sound that developed when accelerating and slowing down. I went on the interstate to try and re-create the error. Sure enough, after 20 minutes of driving ~70mph the lights came on.

    I did a bunch of searching on this forum and google and was hoping it was the inverter coolant pump, but there was always turbulence in the reservoir. So I went to O'Reilly auto parts and used their OBD2 reader. The two main errors were P0A2B and P0A37 (Drive motor "A" temp sensor range/performance, and generator temp sensor range/performance). The other errors were left and right front wheel speed sensors (C0200/C0205), Accumulator low pressure malfunction (C1256), malfunction in HV system (C1310), open circuit in main relay 1 (C1311), open circuit in main relay 2 (C1313), capacitor malfunction (C1377), and U0293 (no communication or something to that effect).

    I'm assuming all the other errors are just byproducts and that I just need a new transaxle, found a good price on a used one and want to tackle the job myself. I'm no mechanic but I've always worked on my own cars and can follow a write-up. But I've never worked on a hybrid.

    Is there things that I should know before trying to do this myself? What other things should be replaced while there (gaskets etc)? And most importantly, is there a DIY writeup somewhere for replacing the transaxle?
     
  2. 3prongpaul

    3prongpaul Hybrid Shop Owner, worked on 100's of Prius's

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    James Analytic likes this.
  3. Lavalamp

    Lavalamp Junior Member

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    Awesome, thank you.
     
  4. Lavalamp

    Lavalamp Junior Member

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    Alright I got the old transaxle out and I'm in the process of transferring connectors/hoses/etc to the replacement.
    Is there any seals I should replace before I put this other one in?
    Should I flush it out (how?) to remove any debris that might have gotten in there while sitting at the salvage yard. If so, would it be fine to use cheap transmission fluid to flush it with and fill it with the recommended toyota fluid when done?
    Does the torque converter have to line up a specific way on the spline?

    Did I mention I've never replaced a transmission before?
     
  5. 3prongpaul

    3prongpaul Hybrid Shop Owner, worked on 100's of Prius's

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    Check the axle seals, they don't usually leak but if they were leaking now is the time to change them. Note, L&R seals are different part numbers. The tranny is pretty much sealed so nothing should have gotten inside unless debris got in through the axle holes. I would just drain all the fluid out of the 10mm (Allen/Hex) drain plug. Once tranny is back in the car and axles installed fill with 3.9Q of Toyota WS fluid via the fill port on front of tranny. (buy new aluminum crush washers for drain and fill plugs from dealer).

    There is no torque converter or flex plate on a Prius, even though it is an automatic.
    The transaxle input shaft mates with the ICE "flywheel" in any position, just like a "normal" car would with a manual transmission.

    Lastly, how long did it take you? Other newbies are curious I'm sure.
    Pmail me any changes you think I should make to my "pull" document referenced above.
     
  6. Lavalamp

    Lavalamp Junior Member

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    I'd say it took me about 7-8 hours, split in two days, to get the transaxle out. I've never done any sort of work involving a transmission before so I learned a lot these past couple days. I worked slow, made a few trips to the store, installed an engine hoist, took some snack breaks, etc.

    Your writeup was great and definitely helped a lot. I did make note of a couple things that could be added/changed but nothing major. I'll message you when I get everything back together, which I think will be the hardest part.
     
  7. Lavalamp

    Lavalamp Junior Member

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    Oh also, the replacement transaxle had all the wires cut so I have to open it up to transfer the big orange wires. What kind of sealant should I use to seal it back up (the factory stuff is pink looking).

    [​IMG]
     
  8. 3prongpaul

    3prongpaul Hybrid Shop Owner, worked on 100's of Prius's

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    Spray the tranny "spike" and rubber mount with WD 40 before lifting the tranny up into the tranny mount. It will go in easier lubed up.
     
  9. 3prongpaul

    3prongpaul Hybrid Shop Owner, worked on 100's of Prius's

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    That blows.

    I should have mentioned to make sure the yard monkeys at your salvage yard don't cut the big orange wires...they should have disconnected them from the inverter end. No you have an extra hour or so of work and the potential for future leaks if you don't seal it well. Throw away the flywheel they supplied (it should just pull off), the one you left on your engine will be fine.

    Best to lay the tranny on it's back and have the end cap facing up. Do it over a drip pan or cardboard because it will most likely puke fluid.

    Remove the bolts around the perimeter of the end cap and gently tap it off little by little. If you look closely you'll see little ears that are designed to bang on to remove it. Don't remove any bolts near the center of the end cap.

    Best to get the (expensive) tranny sealant from the dealer. They may have to special order it.
    If you don't want to wait, I would use THE RIGHT STUFF (yes it's really called that) from your FLAPS.

    When end cap is off carefully clean off old sealant. Use very little when putting it back together and make sure everything goes back the same way. Tap the cover on first gently with a rubber hammer then insert the bolts and torque carefully. You don't want them overtight or they may strip the tranny case.
     
  10. Lavalamp

    Lavalamp Junior Member

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    Thank you for all the info, I really appreciate it.

    One last thing (I hope), the "new" transaxle doesn't have the aligning dowel in it like my old one does. I tried removing it to use it but I doubt it'll be useable by the time I get it out. I'm guessing it won't hurt anything if I don't use it, besides making it a little harder to bolt up, right? (I still have one on the engine side)
     
  11. 3prongpaul

    3prongpaul Hybrid Shop Owner, worked on 100's of Prius's

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    It's best to use the dowels but you could probably skip one if you really had to. It the yard local? Perhaps go over and ask them to pull one for you from another tranny...they are probably the same on many Toyota trannies. Dowel part number is 90250-10113 only $1.26 list price but probably special order at dealer.
     
  12. Lavalamp

    Lavalamp Junior Member

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    No they're a couple hours away.
    I'll go ahead and order one online along with a couple other things. I've had nothing but bad experiences at the dealer here so I'd rather not give them any money. I'm not in a rush so I'll just wait a few days for the stuff to get here.

    Would you happen to have a part # for the tranny sealant?
     
  13. Lavalamp

    Lavalamp Junior Member

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    Found the part # for the sealant: 00295-01281

    Also found out these cars don't have transmission fluid filters, one less thing I need to order.
     
  14. Lavalamp

    Lavalamp Junior Member

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    Alright, got most of it back together. Couple questions.

    a) Where is the ground strap that connects to the inverter? I don't remember re-attaching it (or taking it off in the first place) and don't see it anywhere.

    b) Where is the bleeder screw for the coolant? Is it the one that is attached to the inverter? The're a sticker under the hood that says it's on the side of the radiator but I don't see that.

    c) How do I refill the transmission fluid?
     
  15. cwerdna

    cwerdna Senior Member

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    Once you're done, I wouldn't be surprised if someone in your neck of the woods wants your bad transaxle for analysis/tinkering.
     
  16. 3prongpaul

    3prongpaul Hybrid Shop Owner, worked on 100's of Prius's

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    a)AFAIK Gen2 inverter has no ground strap, but the tranny itself does.
    (but Gen1 inverter has dedicated ground strap).

    b)Yes, you bleed the inverter/tranny coolant with the 10mm bleeder nipple on front of the inverter. Run a clear hose from the nipple into the inverter reservoir. Turn car on, open valve until air stops going through line. Drive the car for a day or so then repeat just to make sure you got all the air out. Use Toyota "pink" (pre-mixed) coolant on Gen2's

    c)Make sure transaxle was completely drained (open 10mm hex drain plug to check)
    The 24mm Fill plug is on the front of the transaxle, a couple inches up from the bottom.
    Have car level, use a funnel with long hose from above or pump system from below to install 3.9Q of Toyota WS fluid. If fluid starts puking out of filler plug you put in a bit too much.
     
  17. Lavalamp

    Lavalamp Junior Member

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    I got it all back together, figured I'd try to start it before I lowered it back down, and it won't start.

    If I press the power button with my foot on the brake the car turns on like it normally would but instantly shows the Big triangle light and a problem warning on the MID. It also does not let me turn the car off with the foot on the brake.

    Without the foot on the brake I press the button twice, and same thing except I can turn the car off with the foot off the brake.

    I pretty sure I plugged everything back but I may have missed a plug on the inverter. After I unplugged them all I decided I should count them to know how many to plug back in and I counted 13. When I plugged them back in I counted 11 because one of the 13 was for the wipers and I may have counted the plug on the driver's side of the inverter with the yellow sticker on it (though I didn't actually unplug it I just unbolted it).

    The tranny I think only had 4 plugs and I got all of those.

    I don't think O'reilly Auto Parts usually loans out their scan tool but maybe I can get them to let me take it home for a few minutes.

    Any ideas on what to check or how to figure out what's wrong w/o an OBD2 scan tool?
     
  18. 3prongpaul

    3prongpaul Hybrid Shop Owner, worked on 100's of Prius's

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    Double check orange plug on HV battery (if you removed it).
    Very common mistake for people who remove the orange plug the first time.

    There are three steps to putting it back in on Gen2 (and similar on Gen3)
    1) Insert plug
    2) flip lever up
    3) Press lever straight down (this allows it to mate with small 2 pin sensor on the connector/plug)

    If you don't do step #3 car will immediately code when you try to power up.
    Once car codes, fix step 3 then try restarting again 2-4 times. Car should READY up and dash lights should clear.
     
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  19. Lavalamp

    Lavalamp Junior Member

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    Ahhh, I hope that's it, I didn't do step 3. Though I can see the charge level of the HV battery on the MID.
     
  20. Lavalamp

    Lavalamp Junior Member

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    Well that was it. Took it on the interstate for ~40 mins at 75mph and no error. It previously only took about 20 mins for the error to pop up at those speeds.

    Now I need some new wheels/tires because these ride horribly.

    Thanks for all your help Paul, I couldn't have done it without you. I'll post up a few notes later tonight.
     
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