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HV Transaxle cooler/filter

Discussion in 'Gen 2 Prius Technical Discussion' started by IFixEm, May 16, 2006.

  1. IFixEm

    IFixEm New Member

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    [attachmentid=3467]
    There was some discussion recently here and offline into the feasibility of a transmission cooler. I made one and it works but I am not totaly convinced of the need at this point (lack of unit failures). I did make an added bonus to the system with the use of an external sediment filter. The filter is clear so fluid color and condition can be easilly assessed during the 5k service. The installation time is about 40 minutes with no special tools, and only basic mechanical aptitude. It's on par with an EV switch. The ambient temps today were 75ish, low humidity. Test vehicle, 01 prius 74K. After a 45 minute road test at lunch and another after work, it seemd to cool MG2 by about 8-15 degrees over yesterday's run. Not very scientific I know. The oil is definately cooler...130 going out, 95 going in using digital thermometer. Does it work to keep MG2 cool? I think so. Is the oil cooler? Yes. Is it easier to keep clean? Yes. If the filter plugs will my gears starve for oil? No. Wiil the oil get to cold in winter? No.

    Some initial pics.........
    [attachmentid=3468]

    Run the lines behind the radiator support.

    [attachmentid=3469]

    There was room for a filter so...

    [attachmentid=3470]

    Oil pump location, 4 screws removed to take splash shield out

    [attachmentid=3476]

    Version 1.0a

    [attachmentid=3471]

    This filter requires changing, and the oil needs serviced. Visual inspection at a 5k intervals prevent the "crude oil" look some Prius have experienced.

    [attachmentid=3472]

    This oil is clean.

    [attachmentid=3473]

    Oil will flow thru this drive shaft and help cool MG2 PM and bearings.

    [attachmentid=3474]

    Oil exits the planet carrier shaft and lubes the pinions (port is hidden from view), and MG1 sun gear, inner and outer bushings.

    [attachmentid=3475]

    Oil level is about 20mm below (to the right) of my hand and helps cool the windings, and lubricate the differential assembly and SDC. Your Input requested.

    Regards, Mike
     
  2. efusco

    efusco Moderator Emeritus
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    Mike,
    As I understand your modification you're simply using the existing oil pump to pump the oil through MG2. That makes sense for convenience. But, as you mentioned, it seems that this might be nothing more than adding a belt when already wearing suspenders. At least with my '04 Prius MG2 temps seem to stay within a reasonable range...though I haven't been able to monitor those temps during the peak of summer heat.

    Now, one issue brought up amongst the PHEV crowd has been that the oil pump is run via the ICE. When they're running for longer distances in EV mode there is no oil being pumped and there's some concern that over long distances they could be doing some damage to the system as the Prius wasn't designed to be a long range EV.

    One individual I know has created a seperate electrical pump that keeps the MG lubed via the 12v battery (though with the existing coolant system, not via a seperate radiator). If I had a suggestion I guess that would be it. Look at MG2 temps (and inverter temps) over longer EV runs before and after an electric coolant pump is installed...I suspect your variance from baseline will be much greater.
     
  3. viking31

    viking31 Member

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    Great idea but I would be concerned about a few items regarding the installation.

    I would prefer steel braided hoses with flare nut to nipple connections rather than hose clamps. These oil lines are important and unlike a radiator hose failure, failure of these lines could lead to extensive damage to the components it serves well before the operator of the vehicle is aware of the failure. The clear filter is also unique but again as with the hoses I would prefer at least a steel shield of some sorts to protect the plastic filter. In addition, the filter should also have some sort of bypass mechanism in case of clogging or excessive load.

    Rick
    2006 #4
     
  4. FireEngineer

    FireEngineer Active Member

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    Mike, did you add extra oil to the transaxle to account for the oil in the cooler? If so how did that affect the transaxel breather when the oil was not running in the cooler-EV mode?

    Wayne
     
  5. IFixEm

    IFixEm New Member

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    I agree. MG2 already seems to run 15* cooler than MG1. Now it's 20-30*. Inverter temps seem to spike easy, but come right back down. Circulating the oil should help to cool the oil and thus lower winding temps, but probably will have no affect on case or inverter temps. It's just not that big of a system. Belt/suspenders is funny, I was thinking maytag repair guy that came up with a better dryer sheet. I'm not sure this qualifies for belt status because belts work by themselves.
    I think (FWIW) that extended ev will not be an issue. The diff carrier sits immersed in oil, so the SDC should sling oil onto the Planet assy anytime the veh is moving ice on or off.
    [/quote]
    Looks like a far better idea for cooling, but I like being able to see the oil, sticking a finger in the hole is hard to get a good color reading. You have probably more time looking at prius data than anyone else including Toyota techs (me). We are after specific problems or working on camrys. I especially appreciate your input Doc.
    Regards, Mike


    The cooler is not higher than OEM oil level, so drainback should not be an issue. It took .6 quarts extra.
    Regards, Mike

    I went sorta cheap on the first one because I bought the parts for my customer ( sans oil) so I went with rubber oil hose. There is a bypass mod in the pump so that if a line got pinched you will not starve it for oil. I used a plastic A/T valve body check ball from old previa vans and the dual stage sping found under the flint in a bic lighter. I was quite scared of this actually, starving the guts that is.
    Regards, Mike
     
  6. hdrygas

    hdrygas New Member

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    Very Very nice. How might this fit in with my radiator blocker, I have not yet been through a summer to monitor the temps on the inverters and windings. I am taking the blocker off tomorrow even though in the past several warm days I have not seen a change over the winter temps with everything blocked up. I need to know the "norms" for summer driving. I am looking for a few 90 degree days. OK go ahead and laugh you folks in the sunbaked south land, but between the mild climate and the radiator blocker and the block heater I may yet give you a run for your money. I just need to know how hard to push things and what the normal summer range is. I would appreciate input from people with the Can View with OBD II mod on the inverter and winding temps in summer conditions, your summer not mine!
     
  7. sub3marathonman

    sub3marathonman Active Member

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    <div class='quotetop'>QUOTE(IFixEm @ May 16 2006, 12:19 AM) [snapback]256121[/snapback]</div>
    I just had a question about "Version 1.0a." How did you go from the top picture of the original oil pump to the second picture of "Version 1.0a" with the oil lines attached? Were there two plugs that you removed and then replaced them with the hose fittings?
     
  8. grasshopper

    grasshopper Member

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    <div class='quotetop'>QUOTE(hdrygas @ May 17 2006, 02:10 AM) [snapback]256709[/snapback]</div>

    How are you monitoring your temps? You mention Can View with OBD II mod on the inverter and winding temps. I don’t know what all that means. Are you able to see these temps on the MFD, or is it this OBD II mod that allows you to see the temps? I want to have temp gauges for the ICE oil and transmission fluids. Do I need to just have some gauges installed? Are there sensors already installed or is that something I need to get also. Will this OBD II mod do all of that for me? Obviously I don’t know what an OBD II mod is and with just a package #3, maybe I don’t have all I need to install it anyway?
    I pull a trailer and feel that I defiantly need to monitor the temp’s real time. I have been following this subject, but I admit that I don’t know enough to understand what ya’ll are doing. Can someone take the time to explain some of this to me, or just how to install some gauges?
     
  9. IFixEm

    IFixEm New Member

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    <div class='quotetop'>QUOTE(sub3marathonman @ May 17 2006, 06:21 AM) [snapback]256800[/snapback]</div>
    There is one plug (bolt) for checking oil presure...all blistering 5-13 psi of it. I replaced that with a cold start injector bolt from a 22re or 3vze I'm not sure. I then put a cold start fuel line on it and connected a hose. The second hose home needed drilled and tapped to accept my new fitting, modified an internal pump passage and there it is. First one in captivity. It cost me $7 for the bolt, 5 for a fitting, the cold start line was floating around here. The cooler and hoses were $36. Pretty cheap mod...wish it worked better, but it still has some upsides to it I think. The customer is a great guy, and has multiple hybrids. I think this Prius was one of the first the dealer sold. I appreciate everyones input.
    Regards, Mike
     
  10. hobbit

    hobbit Senior Member

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    I was gonna say, outout pressure from that pump is pretty
    minimal so it seems unlikely you're going to blow hoses off the
    fittings from that. Sure, flare fittings for high-pressure stuff,
    but here, the oil just lazily circulates.
    .
    The mod target is still a running car, right? As opposed to the
    toasted-MG2 transaxle you've got apart but can use to model some
    of this stuff? It's great that you've got that to play with and
    can keep taking all those wonderful pictures.
    .
    Did you ever figure out *what* toasted that motor, BTW?
    .
    _H*
     
  11. rick57

    rick57 Member

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    HI Mike. What got you ( or the customer ) thinking about adding a cooler? There can't be that much of problem in the transaxle to warranty a cooler install and I would assume that most people don't even tow with the Prius. Reasoning for the mod besides lower temp? Longer life maybe? Longer fluid life? Good installation,explanation of steps and pics.
     
  12. IFixEm

    IFixEm New Member

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    <div class='quotetop'>QUOTE(rick57 @ May 17 2006, 08:40 PM) [snapback]257313[/snapback]</div>
    (Long response)

    I started to see a few Pri's with dark oil on my finger at lower than expected mileage. Hdrygas who is a local to me, posted not long ago about the same thing. I was recently at a Toyota new model class and some of us were talking about it there in a side conversation. Turning dark has no established pattern as to use yet. Some cars have had EV mods and others without and low MPG history. Often that is an indication of less load in the motors and more ICE time than EV + Pulse and Glide folks. There is no indication at this time that P&G is harder on anything yet.

    My observations have been that it looks "not good" on the finger and "horrible" when drained. It gets dark purple or even black once it starts to come out. You can see what appears to be trace metal in it because it sparkles in the light. In my 22 years (15 at this dealership), I have noted this: not all toyota transmissions that look this way fail, but all that fail look this way. Camry, corrola, sienna, van...they all had the silver flake in the oil. So Prius oil is expensive, but labor is cheap. It's an easy DIY for those that do. My logic would follow that its a good idea to exchange the fluid, Prius or other platform. The box has a strainer but no filter, and several small wafer magnets the size of a nickel. The only MG2 magnet I have seen also had metal on it.

    The common thread may end up to be the differential failing and contaminating the oil. This is not the customers symptom of failed yoda fwd boxes but it is usually the root cause. I was the only tranny guy the shop had for many years. I am still the go to question guy and if it an A/T gets O/H I did it. I have more experience inside toyota and GM transmissions than 95% of the "technicians" out there. Simple cure is to change the oil early and often. 30k would not be a bad idea and definitely by 60K is what I am starting to think. Differentials, by their nature, must make metal. Unfortunately the metal is such a fine powder it never comes out of solution and settles in the pan. The magnets do what they can as it floats past. Valve body and cast hard parts but not the aluminium case is where you find most of the the grey film. I think all the magnets do is polarize the metallic oil. An easily changed filter might capture some of this. You can now flat tow your prius with an electric pump and my system behind your diesel pusher RV. :lol:


    There has always been tempered concern with inverter temprature spikes for those that have the ability to see the data (buy a can-view now!!). The heat created in the use and generation of the amperage is dumped to the case to be cooled via air , oil, and primarily by a dedicated cooling system. There are cooling system mods for both cooling and mpg. Frank has a classic mod for mpg that I love. Henry's Gen 2 mpg mod is stealthy like the car. The oil cooler and filter mod I tried was an attempt to address ease of accurate 5k fluid inspection as well as case cooling. I think one worked well and one so-so. I am going to have him come back in a few weeks or 1k. I might see if he is willing to make a R/T with a cell phone and THHS in each car on a good long run. Perhaps a local would come out to play, or I wait for a trade in. I can also shorten the cooler loop to a few inches total system length easily in the field. Thats what will probably happen. I need more scan time to look at nominal winding and inverter spike temps. Locally they seem to run warm but not hot, and everywhere they run a little hotter on MG1 side.

    Actually it's an expensive, simple but well made box. I did not have my hopes up of improving much on the prius initial design. I don't think many will fail, but the fewer the better for us all. FWIW I did this off the clock and if the system fails, I will be FixenEm after hours with parts on my dime. Why did I do it? I like the product platform and many of the customers are fun to hang with.
    Regards, Mike
     
  13. sub3marathonman

    sub3marathonman Active Member

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    <div class='quotetop'>QUOTE(IFixEm @ May 17 2006, 06:33 PM) [snapback]257184[/snapback]</div>
    A couple more questions based on this response.

    First, what is a "22re" or "3vze?"

    Also, if you "drilled and tapped to accept my new fitting, modified an internal pump passage," then you must have removed the entire cover to do that? And why did you have to modify the internal pump passage? Did you drill and tap the new fitting so it was the same size as the place for checking the oil pressure? What could you do to make it work better?

    It seems like a great job that would really help with longevity of the fluid.
     
  14. Frank Hudon

    Frank Hudon Senior Member

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    First, what is a "22re" or "3vze?"
    these are Toyota engine model numbers.

    Mike the more I look at this the more I'm start to think I want one, not the cooler part but the filter aspect is what intreges me. That filter with a semi-circular magnet epoxied to the outside to capture and hold the "metalic" out of the ATF has me thinking. Like yourself the metalflake is a sure sign of immenent failure especially any clutch type autobox I've had the delight to overhaul. And to be able to remove and retain it in the filter would be a great asset for the car. Now to get the parts and install it. When we were talking at Lacey about this I just had to check my ATF so did a UOA and will have the results next week. Let me know when you have the pump covers in "stock" and I'll get it.
     
  15. Skyjim

    Skyjim New Member

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    Perhaps a small bypass filter to capture those metal fines from the diff would be a good setup - that way there would be the ability to run a smaller micron filter without compromising flow and you'd retain cooling even with a clogged filter - if somebody makes a filter small enough to fit in the space available.

    I've got a bypass filtration system on my diesel truck and the ATF stays beautiful! I do change it annually (not a lot of miles put on it - tow vehicle only) and watch tranny temps while towing. This is the one I've got, just FYI - too large for a Prius installation, I know. Their assertion that it dissipates some heat strikes me as a bit of a reach, but my ATF stays clean!

    Dieselsite transmission filter kit

    Jim
     
  16. jayman

    jayman Senior Member

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    Mike:

    I appreciate the time you took to figure this out. I did a CVT fluid change at around 12,000km and was surprised at how dark the fluid already was. I intend to change it again this summer with around 60,000km and will report the condition.