Gen1 tranny service DO IT NOW!

Discussion in 'Knowledge Base Articles Discussion' started by 3prongpaul, Aug 27, 2010.

  1. 3prongpaul

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

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    After replacing about a dozen Gen1 (2001-2003) Transaxles for various people I decided to document the fluid change procedure so most driveway mechanics can do the service themselves....and hopefully save them the hassle and expense of replacing the tranny down the road. If you do not change the Gen1 fluid properly, the contaminated fluid plugs the input screen, tranny doesn't get enough lubrication and it overheats/destroys itself.

    If you have not changed the fluid and cleaned the pan/input screen in the last 30,000 miles, do it soon...too many Gen1 tranny's are blowing up because dealers only drain fluid and refill, they do not clean the pan and input screen.

    The fluid service is much less expensive than replacing the transaxle. I'll say it again. Service your Gen1 tranny now!

    If you take it to a shop, insist the mechanic drops the pan, cleans the pan, magnet, and input screen.
    The dealer does not typically do the procedure this way, so insist it gets done properly. Print this out and take it to your mechanic if you have to.


    Note, Gen2 and Gen3 Priuses don't have a pan to drop...supposedly the design is better and you are less likely to destroy the tranny on a Gen2 or Gen3.

    DIYs should buy from the dealer;

    4.9 quarts ATF WS (WS is better than ATF IV for Gen1 in my opinion)
    1 pan gasket 35168-47010
    2 crush washers 90430-18008 (for fill and drain plugs)

    Optional;
    1 O-ring for pickup tube 90301-11019

    You'll also need ramps/jackstands, rags, paper towel, gloves, clear hose, funnel, etc.

    Full photoguide here; Gen1 Prius Tranny Service
     
    PDX_jsf, edthefox5 and ericbecky like this.
  2. don_chuwish

    don_chuwish Well Seasoned Member

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    Great contribution, love the photo guide. Almost makes me wish I had a Gen1 to work on. :)
     
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Nice guide. It is true that ATF WS is used in 2G and 3G Prius, but that does not necessarily mean that WS is better for the Classic transaxle.

    Since ATF T-IV has thicker viscosity than ATF WS and the Classic transaxle was designed for the use of T-IV, it is possible that the use of thinner WS oil could negatively impact transaxle life.
     
  4. 3prongpaul

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

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    I guess it's possible. Gen1 and Gen2 transaxles are mechanically very similar. My rationale is since lots of Gen1s are dying with ATF T-IV why not use ATF WS (since Gen2 trannys almost never die).

    Any Toyota engineers out there know the correct answer to this question?
     
  5. tochatihu

    tochatihu Senior Member

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    Thanks for preparing and sharing this excellent guide! As you note the pan bolts are originally with locktite, what do you think about also using it for reassembly?

    I agree that some controversy exists about T-IV vs. WS in the NHW11 transaxle. Higher particle loads when WS is used as replacement would certainly be strong evidence against. Bob Wilson may have data on that. I guess the crux of the matter is whether the bushings (already worn to some extent) have a thick enough lubricant film with the WS to avoid further metal wear when operated at temperature.
     
  6. 3prongpaul

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

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    There is enough residual locktite on the bolts you don't have add anymore. Just be careful not to over tighten them, best to use a torque wrench set to 67 inch pounds.
     
  7. Montex

    Montex Junior Member

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    I would not 'reuse' Locktight. Put a couple of drops on each bolt and torque them to the proper spec.
     
  8. ericbecky

    ericbecky Hybrid Battery Hero

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    This is an excellent guide. Clear and concise. I was able to do one of these jobs with Paul and see first-hand the junk still in there even though the customer had just gotten service done by the dealer.

    Great contribution Paul. You and the guys at 3Prong Power are one of the few independent repair guys out there that I'd trust my car to. Thanks for giving back to the community!
     
  9. edthefox5

    edthefox5 Senior Member

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    Thats what I thought too Patrick. I have read somewhere that there's a difference in CVT bearings between Gen 1 and 2. Gen 1 uses open races and more copper in there CVT bearings and is dependant on cvt fluid for lubrication. This was why I think Bob found excessive copper leaching in an uoa when he ran Amsoil in his Gen 1 cvt.

    I have read Gen 2 uses sealed bearing races. Superior bearings to Gen 1 I would imagine. Which I surmise allows use of a thinner fluid in Gen 2's as the only thing your lubricating with the WS is the planetary gear system and chain. And increased mileage because of it.

    To be honest I'm speculating here about things I have read on the Internet concerning this.
    It would be excellent if someday you could pull apart a failed Gen 2 and see if the bearings are really sealed like a wheel bearing.

    But if I am right Gen 1 may be more dependant on proper fluid viscosity & lubrication for its bearings. And I suspect is why Gen 1 cvt's are much much harder on there fluid and as the OP suggests a heightened interval for fluid change is wise.

    Using WS in place of T-IV may not be a good idea on Gen 1. But a good post for fluid change how too. Thank you.
     
  10. xs650

    xs650 Senior Member

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    Sealed bearings inside a transmission sounds strange. :eek: Given the choice between the puny amount of any type of lubricant I could put inside a sealed bearing vs an ATF batch of a few quarts, I would go for the ATF every time.

    Gen III uses WF also and it's bearings aren't sealed.
    http://priuschat.com/forums/attachm...axle-compared-others-2010-prius-transaxle.jpg

    WF is also used in several regular Toyota auto transmissions.

    Edit: Here's a Youtube video of a Gen II transmission showing the bearings don't have seals.
     
  11. bretaz

    bretaz Member

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    In 2004, I started having problems with my 2003 that had 74k miles on it. They told me it was the inverter, but that it was under warranty. I picked up the car and it broke down again 10 miles later. They told me it was the transaxle, which was not under warranty. However, Toyota "goodwilled" the repair. The inverter, transaxle, two tow bills, and two weeks of a rental car would have been around $15,000.00 if I had to pay for it. I got it back on a friday, and traded it in the next day for an xB.

    In all fairness, these problems all started after a front collision. I still think it was related.
     
  12. edthefox5

    edthefox5 Senior Member

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    I agree. I notice in the G2 service manual it states one of the improvements in the Gen 2 CVT is ball bearings for its bearings.
    For its exceptional quietness.

    It makes no mention of what the Gen1 is. Sealed bearings in the 1 does not make alot of sense so maybe sealed is not right. I agree with that. It needs fresh lubrication. Maybe Gen1 uses needle bearings? I don't know.

    But it must be different than Gen1 or they would not mention it in the manual. The evidence is whatever there using in Gen1 is much harder on the fluid than G2 so they made an improvement in bearing style.

    So maybe not sealed but using ball bearings instead of what?? I don't know. Whatever it is its an improvement. The only way to tell is to take the trans apart and from what I have seen thats not an easy job.

    But for sure if you have a GEN1 Prius change the fluid!!

    My G2 cvt runs really good with Redline D6. A very well designed transmission.
     
  13. Saquibs2004

    Saquibs2004 New Member

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    Can we see a guide like this for replacing the Coolant?
     
  14. Irrenarzt

    Irrenarzt Junior Member

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    Thanks for posting this guide. I am doing this now and all I need to do is pump in new fluid. Great guide and this was very easy to do. I noticed another 24 mm plug to the left of the drain plug on the removeable pan. Not the fill plug above but on the next section over and appears to be another drain plug. Is this a differential? I have the Haynes manual but it mainly shows the Gen2 service pics so I'm not sure.

    I would second the call for a coolant change guide should an expert be willing to do so.

    But thanks for the effort. It is much appreciated.
     
  15. Irrenarzt

    Irrenarzt Junior Member

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    Pumped in the ATF and sealed her up and drove for about 50 miles. She's all good.

    My only concern is when you pull out the tube with the screen to replace the o-ring is that it is kind of a bitch to get it back in. I think I got it but the gland that the o-ring sits in is not that great (a bit of side to side slop). This could happen (from that MG2 rebuild on Art's Automotive page), leading to transaxle failure:

    [​IMG]
     
  16. Irrenarzt

    Irrenarzt Junior Member

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    I'm wondering if there is a need to do this on the gas engine side? There is also a steel removable oil pan on that side but I see no mention of people doing this. I realize you change that oil much more frequently but there could still be a sludge buildup on the pan which could lead to problems...
     
  17. lusciousgarage

    lusciousgarage New Member

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    A response to the notion that you have to drop the pan to service this transaxle "properly", and the o-ring myth.

    LG advocates drain and fill every 30k, with T-IV.

    (Likewise we do not drop the engine oil pan for oil changes...)

    Others will argue greater caution, but there is a penalty in over-servicing (higher cost) with no guarantee stator windings will last longer.

     
  18. That_Prius_Car

    That_Prius_Car Austin Kinser

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    I just changed mine this morning, first time it's ever been changed in 11 years and 105,000 miles. Here are some pictures I took of the process. The gunk and metal shavings were terrible!! 1001351_552920001410084_101118969_n.jpg 1016716_552947948073956_974240063_n.jpg 1016700_552920464743371_1852855552_n.jpg 1044972_552920544743363_1169828747_n.jpg 944200_552920154743402_1701154716_n.jpg 1566_552920288076722_1501191920_n.jpg 1004002_552920414743376_526063976_n.jpg 935008_552920628076688_2009365523_n.jpg 1004782_552920768076674_1183777056_n.jpg 945102_552921038076647_85319497_n.jpg 1044996_552921151409969_781227941_n.jpg 935804_552920961409988_1641418245_n.jpg 993619_552921204743297_1426831864_n.jpg 1003474_552948018073949_1054570075_n.jpg 17599_552948131407271_1637308238_n.jpg 7981_552948214740596_102769748_n.jpg
     
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  19. mountain eagle

    mountain eagle Junior Member

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    :cry: I should have done it now..........

    No, it didn't blow up. But the ever so helpful picture link in the first post is now a 404 link............. sigh. Figured I should mention it as I'm sure there's folx like me that just have it bookmarked and not properly saved.
     
  20. Former Member 68813

    Former Member 68813 Senior Member

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    While I understand darker fluid and gray paste on the magnet, what is the source of the gray and white particles in the pan? The metal machining pieces were also horrible. Poor manufacturing practices for sure. This is the worst looking tranny pan I've ever seen.
     
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