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Thread: Having issues with tcc slip while commanding 0. 8l90 circle d triple disc

  1. #61
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    Yes I did, it didn't make any difference. I disabled them by setting both the trans temp and TPS entry parameters to maximum limits.

    The only thing I am convinced that works on this T87A OS is the shift/TCC points and the master switch to enable some form of torque management/reduction during shifts. No other parameters have proved themselves that they work.

    I guess I should open a ticket but I feel like that is "frowned upon".

    Does the "TCC Limit" torque reduction have anything to do with anything or need to be changed from stock?
    Last edited by cmitchell17; 07-22-2021 at 01:46 PM.

  2. #62
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    I also tried using the scanner tools to force lock it, which with the stock torque converter would instantly lock it to zero slip as long as it was going over about 5mph or so even in first gear. Now it might make a very slight difference at low speed when I force lock it with the Circle D converter but seems to have no effect when I give it throttle, the slip just shoots up to 500+ rpms with any good amount of throttle input.

    With it forced locked in the scan tool the TCC pressure immediately reads 495 psi which we know is just some sort of fake calculated pressure.

    I am starting to wonder if I screwed something up installing it, I just don't know how that would be possible. From what I understand the torque converter I have is the same as a stock torque converter, the only thing that has changed is supposedly a newly billet machined stator and a woven carbon clutch that supposedly replaces the stock paper clutch. I always thought after about 2000 or so GM switched to carbon based clutches with so much percentage of carbon since they went full on PWM slip style control. I guess its possible that in the newer 8L90 stuff they switched back to paper since maybe they found a way to make it work with slippage. So either the clutch apply area has decreased a lot or the clutch material that Circle D uses has a lot lower friction coefficient than the stock material and therefore needs a lot more pressure?

    Obviously if that is true we still need proper software control over the TCC clutch.

  3. #63
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    OK, so maybe the TCC Desired Pressure (TCM 5672) may actually be working. I put the maximum value of 594.1 psi into the whole table and tried it. I do feel a very very slight increase in holding capacity but it still will slip at about 25-30% throttle in 8th gear.

    It looks like maybe there is a internal leak in the Circle D converter, which is about the worst thing that could happen given how difficult it is to remove the engine or transmission with no lift in a small garage after all this work. An internal leak is about the only thing I could think of that would make it slip so much even with all that pressure, I don't think the fluid would make any difference, I would also hope that Circle D tests the converter before shipping but I don't know that.

  4. #64
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    There is that lock up o-ring that should be replaced. I presume you did that or didn't pinch it on install.

    Can feel your pain with the lack of tuning available. My 6L90 had all sorts of dramas with an aftermarket verter getting control over lock up. I was working with Joel at VCM support here in Australia to try and get it to work. He's a top bloke and made me his test bitch. He assisted in getting the 'use regulator settings' switch which we used first to get the lockup reg offset working and then later on the 'TCC desired pressure' table which has been the one that got the converter finally sorted now.

    I think reaching out to support would not be a bad idea. If you're happy to do some testing for them of course it helps. Sorry I can't be anymore help to you... HJ

  5. #65
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    Quote Originally Posted by hjtrbo View Post
    There is that lock up o-ring that should be replaced. I presume you did that or didn't pinch it on install.

    Can feel your pain with the lack of tuning available. My 6L90 had all sorts of dramas with an aftermarket verter getting control over lock up. I was working with Joel at VCM support here in Australia to try and get it to work. He's a top bloke and made me his test bitch. He assisted in getting the 'use regulator settings' switch which we used first to get the lockup reg offset working and then later on the 'TCC desired pressure' table which has been the one that got the converter finally sorted now.

    I think reaching out to support would not be a bad idea. If you're happy to do some testing for them of course it helps. Sorry I can't be anymore help to you... HJ
    Thanks for the help its ok haha.

    As for the lock up o-ring, I didn't see anything about an o-ring? and I didn't see anything on any instructions? (even though there weren't really any instructions more just "tips" on Circle D's website).

    Is this lockup o-ring in the valve body under the pan? or is it in the torque converter?

    Its weird to me that torque converters just basically are just put on and that's it. I guess they just spline up like a driveshaft and a yoke. I just don't get how the stator gets properly grounded and planted and especially don't get how it seals fluid especially given that it seems like under a high stall condition there could be a extremely large amount of pressure and you would think it would just shoot out from the hub/shaft.

    I mean I guess its logical to assume that fluid could leak past the apply piston or surface or whatever it is, I think its the actual whole rear cover that moves and presses on the clutch surface.

    I think a torque converter is one of the coolest most interesting things ever though.

  6. #66
    Quote Originally Posted by cmitchell17 View Post
    Thanks for the help its ok haha.

    As for the lock up o-ring, I didn't see anything about an o-ring? and I didn't see anything on any instructions? (even though there weren't really any instructions more just "tips" on Circle D's website).

    Is this lockup o-ring in the valve body under the pan? or is it in the torque converter?

    Its weird to me that torque converters just basically are just put on and that's it. I guess they just spline up like a driveshaft and a yoke. I just don't get how the stator gets properly grounded and planted and especially don't get how it seals fluid especially given that it seems like under a high stall condition there could be a extremely large amount of pressure and you would think it would just shoot out from the hub/shaft.

    I mean I guess its logical to assume that fluid could leak past the apply piston or surface or whatever it is, I think its the actual whole rear cover that moves and presses on the clutch surface.

    I think a torque converter is one of the coolest most interesting things ever though.
    I feel your pain on this, frustrating when a modification gives you so much trouble.

    There are two seals that seal the torque converter apply and release fluid to the converter. The first one is on the end of the turbine shaft(shaft that sticks out of the front of the transmission). It is an o ring, usually black or orange. This should be replaced every time you take a converter off or on. If you cut this o ring you will have an internal leak in your TCC circuit.

    #3 in the picture

    turbine.jpg


    The second one is inside the stator support, which is the housing the converter goes into. There is a blue seal in this housing that you cannot replace unless you disassemble the stator support. I have personally fucked this seal up once( I have built about 30 8L90's so far) when I didn't get the converter straight into the stator support.

    #3 in this picture

    stator.jpg

    Not saying these are your issues but it could be the case.

    I am surprised that Circle D did not include this seal or anything about it in instructions.
    Last edited by cadillactech; 07-23-2021 at 10:46 PM.

  7. #67
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    Quote Originally Posted by cadillactech View Post
    I feel your pain on this, frustrating when a modification gives you so much trouble.

    There are two seals that seal the torque converter apply and release fluid to the converter. The first one is on the end of the turbine shaft(shaft that sticks out of the front of the transmission). It is an o ring, usually black or orange. This should be replaced every time you take a converter off or on. If you cut this o ring you will have an internal leak in your TCC circuit.

    #3 in the picture

    turbine.jpg


    The second one is inside the stator support, which is the housing the converter goes into. There is a blue seal in this housing that you cannot replace unless you disassemble the stator support. I have personally fucked this seal up once( I have built about 30 8L90's so far) when I didn't get the converter straight into the stator support.

    #3 in this picture

    stator.jpg

    Not saying these are your issues but it could be the case.

    I am surprised that Circle D did not include this seal or anything about it in instructions.
    Thanks Cadillactech for the info thats really helpful.

    And the installation tips don't mention anything about it. This is really the first time i've messed with a TC on one of these.

    I had to look and read up and finally found a video on the converter spacing, as the tip is very vague. I found out you have to separate the converter all the way from the flexplate, then measure your total clearance which in my case was .254 in, then Circle D says you want .125 in of spacing. So what's critical is that this spacing has nothing to do with the actual physical spacing at the converter mounting bolts to flexplate, what you are trying to achieve is the proper spacing at the center hub of the converter which you obviously can't see.

    So you take the total clearance after pushing the TC back towards the transmission away from the flexplate and totally separating it and subtract it from that desired .125, so .254-.125=.129. I found some washers at the hardware store (the circle D kit only included a random assortment of 3, 4, and 5 washers and there are 6 mounting holes and you are somehow supposed to get +/-.025in to the target out of that).

    So anyway I got it to .129 in off the flexplate, the thing is could the wrong clearance effect anything? Could it maybe damage that o-ring? I wonder if I even did that right? I did email them and tell them that's what I did for clearance but they didn't seem too concerned about it. You think its possible I may have too much clearance which would push the torque converter too far in?

    What I really don't get is why don't you have to do this with the stock torque converter? I don't remember seeing anything in the service manual about it and I know there were no shims from the factory on the flexplate mounting bolts.

    Also I don't mean to be off topic since this the HP Tuners forum, but I trust people here way more than on any other car forum by far, I wonder if I should just pull the motor again to get to the torque converter, or maybe try the transmission? I do have one of those cheap harbor freight transmission jack that's got a scissor lift on it. I feel after you reach around to try to unplug all the connectors and spill transmission fluid everywhere when unplugging the lines, it might be easier just to pull the whole motor again.
    Last edited by cmitchell17; 07-23-2021 at 11:19 PM.

  8. #68
    Quote Originally Posted by cmitchell17 View Post
    Thanks Cadillactech for the info thats really helpful.

    And the installation tips don't mention anything about it. This is really the first time i've messed with a TC on one of these.

    I had to look and read up and finally found a video on the converter spacing, as the tip is very vague. I found out you have to separate the converter all the way from the flexplate, then measure your total clearance which in my case was .254 in, then Circle D says you want .125 in of spacing. So what's critical is that this spacing has nothing to do with the actual physical spacing at the converter mounting bolts to flexplate, what you are trying to achieve is the proper spacing at the center hub of the converter which you obviously can't see.

    So you take the total clearance after pushing the TC back towards the transmission away from the flexplate and totally separating it and subtract it from that desired .125, so .254-.125=.129. I found some washers at the hardware store (the circle D kit only included a random assortment of 3, 4, and 5 washers and there are 6 mounting holes and you are somehow supposed to get +/-.025in to the target out of that).

    So anyway I got it to .129 in off the flexplate, the thing is could the wrong clearance effect anything? Could it maybe damage that o-ring? I wonder if I even did that right? I did email them and tell them that's what I did for clearance but they didn't seem too concerned about it. You think its possible I may have too much clearance which would push the torque converter too far in?

    What I really don't get is why don't you have to do this with the stock torque converter? I don't remember seeing anything in the service manual about it and I know there were no shims from the factory on the flexplate mounting bolts.

    Also I don't mean to be off topic since this the HP Tuners forum, but I trust people here way more than on any other car forum by far, I wonder if I should just pull the motor again to get to the torque converter, or maybe try the transmission? I do have one of those cheap harbor freight transmission jack that's got a scissor lift on it. I feel after you reach around to try to unplug all the connectors and spill transmission fluid everywhere when unplugging the lines, it might be easier just to pull the whole motor again.
    https://ls1tech.com/forums/automatic...important.html

    I was going to type out why converter clearance is important but lets just have Circle D do that.

    Stock converter clearance is a design specification that wont change if stock components are used, for the most part. Never hurts to check but usually not needed.

    If your clearance is too much, the converter could technically pull out past the inner turbine seal in the stator support but I haven't ever measured how far that would have to be to do that. Seems unlikely.

    When you installed the converter into the transmission, did you stab it in your first try?

  9. #69
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    If I remember correctly, I think the first time I put it on it didn't seat all the way in. I was standing in the engine bay with no engine so I had almost no room. I think I remember messing with it some more and it pushed in farther after that.

    So I also think I went ahead and pulled the engine up to the transmission bellhousing before messing with the torque converter bolts or spacing, but after bolting the engine up to the bellhousing I remember trying to push the torque converter back as far as it would go towards the transmission so I could measure total clearance, and yes I know I should have but I pryed on it some to make sure it was back all the way. In doing so I think I bent the mounting pad a little, but I think that might have gotten bent some other way because I didn't think I put that much pressure on it. The torque converter seemed to slide pretty easily forward towards the engine though so I don't think it was binding up on anything.

    I know for sure there was no binding and the flexplate wasn't pushing against the torque converter when I put the engine up against the transmission, so I think I was good there and the torque converter was fully seated before putting the engine in, I just don't think I did it on the first try, I guess I maybe had to spin it some before it got on in there.

    I never knew torque converter installation had become this fragile and detailed haha

    Last night I think I also started noticing some weird noises like something kind of loose or rattling around and it sounds like its coming from the torque converter area.
    Last edited by cmitchell17; 07-24-2021 at 12:39 PM.

  10. #70
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    Check out precision transmission on YouTube. Search for his 6l90 videos. Bloke is a bible of knowledge.

  11. #71
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    So there is definitely something wrong. I can hear a rattling noise, like something is lose like the torque converter housing is spinning around and hitting something. You can hear it faintly inside the car sounds like its coming from the shifter area and you definitely can hear it up under the car. What's weird is you can't hear the rattling noise when its cold it only comes out once its warmed up.

    I can also feel the transmission is starting to clunk more on the 3-1 downshift coming to a stop. I really hope I didn't damage the pump I don't know how it would have though.

    And thanks ill check him out.
    Last edited by cmitchell17; 07-24-2021 at 06:23 PM.

  12. #72
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    Quote Originally Posted by cmitchell17 View Post
    I got excited when I saw that this thread had been updated and realized this new TCC desired pressure table was added. Then I realized just like 90% of the other stuff we have for the newer GEN IV and V stuff it has 0 effect. I try to be patient and realize how difficult it is to basically reverse engineer this software so we can tune things, but I wish it would be more advertised as beta. I am thankful that at least the most important tables work like the VVE and air model stuff, its just frustrating to have the same problems year after year. I just put in a Circle D HP 1Y with the woven carbon lockup clutch in my 8L90 Camaro and I feel like I am just destroying the clutch and locally overheating it since I can see the pressure come on very slowly and slip comes down some but then kind of hangs and hangs and may eventually go to around 0 as long as there is light throttle.

    Has anyone gotten anywhere on a 8L90 with this? I mean the TCC desired pressure does do something, after you change it you can see where it just edits back this "fake" "calculated" pressure but there is zero physical change to lockup.


    Late to the update, but, in every calibration that I have seen so far that has had this table added, it has worked as intended. I would say to test lockup with your scanner. If it doesn't lockup tight with that command, you have a physical issue.

    -edit-

    Used quick reply on the previous page / hadn't seen this next page yet. Good luck with the repair.
    Last edited by Frost; 07-26-2021 at 08:33 AM. Reason: saw further posts
    Steve Williams
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  13. #73
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    So just for information I found out the noise I have been hearing is supposedly normal in a triple disc converter since if you are in neutral and there is no load on the input shaft the lockup clutches will rattle around until a load is put on it.

    This is enough for me to put the stock converter back in, I know the "gains" from the converter are probably not even measurable especially in the 8L90 and the rattle sound just makes the car sound like a POS, so a converter is definitely not worth it for me.

  14. #74
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    So finally got the motor out again and my hands are killing me. It appears there is absolutely nothing wrong I see. I want to just put the stock torque converter back in I don't think it makes any measurable difference given its a 8L90 and already has 8 gears. I also can't stand the rattle noise it makes because the clutch packs aren't secure in park/neutral, that's just not acceptable and I would defiantly preferer to have the stock torque converter because of that.

    For some reason it won't let me upload pictures.

    https://photos.app.goo.gl/4Dv3a5jou9Vesbox9
    https://photos.app.goo.gl/QQYszzUtoo7X9YtG9

    I guess im just going to put the stock one back in and start putting it back together and hopefully it works. At least if it does work we now have the parameters we need to force pressure on it.

  15. #75
    Quote Originally Posted by cmitchell17 View Post
    So finally got the motor out again and my hands are killing me. It appears there is absolutely nothing wrong I see. I want to just put the stock torque converter back in I don't think it makes any measurable difference given its a 8L90 and already has 8 gears. I also can't stand the rattle noise it makes because the clutch packs aren't secure in park/neutral, that's just not acceptable and I would defiantly preferer to have the stock torque converter because of that.

    For some reason it won't let me upload pictures.

    https://photos.app.goo.gl/4Dv3a5jou9Vesbox9
    https://photos.app.goo.gl/QQYszzUtoo7X9YtG9

    I guess im just going to put the stock one back in and start putting it back together and hopefully it works. At least if it does work we now have the parameters we need to force pressure on it.
    There is a seal inside the trans on the stator support just past the torque converter lip seal that you can inspect if you look in past the lip seal, factory color is blue. I have messed it up once, make sure it isn't folded over or anything before you throw the stock converter back in. If you don't get the converter in straight and keep pushing, its possible to get it hung up.

    Good luck with the factory converter, hopefully it works out!

  16. #76
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    So thanks, I ended up putting the stock converter back on with a new turbine seal oring. I ended up ordering one online but I could only find a kit for $40 with all the seals, it ended up taking way too long to get here, so I ordered one from the dealer who said they would get it overnight, and it took 4 days. So the day I put the stock converter back in I saw another part online for just the seal and called another dealer and they confirmed that part supposedly works for my VIN and they ended up having it in stock.

    Anyway got everything back together and test drove it and thankfully the converter locks now, but before I could test it out with full throttle to see if it slips, I lost all power to the car. After tearing it halfway apart again I found the starter cable grounded out on the heat shield and blew the main battery fuse. Then it turns out you have to buy the whole junction block so I'm out 130+ another 100 in seals.

    So after fixing that issue I can confirm the stock converter works 100% fine. I haven't heard anything from Circle D or else I am stuck with a 8L90 converter that doesn't lock. I guess it could have been that I didn't replace the turbine seal oring when I put on the Circle D and the stock converter is working now becuase I did replace the oring when I put that in, but I didn't see anything wrong with the oring when I pulled the Circle D off I know it wasn't damaged.
    Last edited by cmitchell17; 08-03-2021 at 03:34 PM.