[cmitchell17]

Originally Posted by Trochoidal

Well your mating surface would be the machined face of the rear cover. The piston itself would have the clutch and of course additional clutch(s) added to go between the rear cover and the piston face. So yes, I could see if the piston wasn’t getting full pressure the lockup never makes contact/engages.

I don’t know if any more failure modes since your using Circle D. I wouldn’t expect the rear cover to have any issues from a metallurgic standpoint since they’re machined and not stamped.

Do you have older logs with trans temp when the lockup was functioning? I’d expect your trans temps would have elevated slightly without the lockup functioning.

Also, if for some reason the lockup was slipping, your trans temp would also elevate.

Just putting out a couple of diagnostic thoughts

So in all my older logs with the stock converter I never logged the trans temp PID. With the stock converter even though I commanded it to lock right when it shifted into second gear, it will slip all the way through second with 200 or so RPM of slip while slowly ramping up the pressure. You can see here it only begins to lock at the very end of 2nd gear with the stock converter:


I have been looking at trans temp on the dash display but even driving on the highway with high load and completely disabling lockup (since I don't want the lockup clutch slipping) it never gets above about 150-160 F even in 90F + outside.

With this new "TCC Desired Pressure" I think we can now have control over the TCC but in a backwards kind of way, since the apply ramp tables still do nothing, but at least we can just force it to a certain pressure with this new table.

But even when I max out this table its not nearly enough pressure to even make any sort of noticeable difference with the Circle D converter installed.

I honestly don't see a converter making enough of a difference to matter given the 8L90 gear ratios, I think its just as important that it locks a little before midway into second so you can get the benefits of it slipping during the shift extension but have it locked to eliminate inefficiency. I guess this is about what it does with the stock converter with the stock TCM tune but it is a little slow it seems like.

[Trochoidal]

Originally Posted by cmitchell17

So in all my older logs with the stock converter I never logged the trans temp PID. With the stock converter even though I commanded it to lock right when it shifted into second gear, it will slip all the way through second with 200 or so RPM of slip while slowly ramping up the pressure. You can see here it only begins to lock at the very end of 2nd gear with the stock converter:
Attachment 1075114

I have been looking at trans temp on the dash display but even driving on the highway with high load and completely disabling lockup (since I don't want the lockup clutch slipping) it never gets above about 150-160 F even in 90F + outside.

With this new "TCC Desired Pressure" I think we can now have control over the TCC but in a backwards kind of way, since the apply ramp tables still do nothing, but at least we can just force it to a certain pressure with this new table.

But even when I max out this table its not nearly enough pressure to even make any sort of noticeable difference with the Circle D converter installed.

I honestly don't see a converter making enough of a difference to matter given the 8L90 gear ratios, I think its just as important that it locks a little before midway into second so you can get the benefits of it slipping during the shift extension but have it locked to eliminate inefficiency. I guess this is about what it does with the stock converter with the stock TCM tune but it is a little slow it seems like.

This is interesting to me because early on in ownership of my car, I became rather observant of the transmission. Back at my original post (link below) I had learned about the shudder. Having the background of building converters I started digging to learn more about what was happening and wanted to monitor the situation to see if I could proactively catch the shudder before it happened.

Since that post I’ve watched pressure, shift times, slippage and trans temp. Having the Banks gauge gave me the ability to monitor daily without needing to have HPT/tablet in the car. For me, I don’t recall ever having trans temps creep out of the 130°s. I’m going to see how far the dash gauge is off from what’s coming from the computer to see if the numbers ever get to the 150°-160° range like you have noticed.

https://www.camaro6.com/forums/showthread.php?t=554779

[cmitchell17]

Originally Posted by Trochoidal

This is interesting to me because early on in ownership of my car, I became rather observant of the transmission. Back at my original post (link below) I had learned about the shudder. Having the background of building converters I started digging to learn more about what was happening and wanted to monitor the situation to see if I could proactively catch the shudder before it happened.

Since that post I’ve watched pressure, shift times, slippage and trans temp. Having the Banks gauge gave me the ability to monitor daily without needing to have HPT/tablet in the car. For me, I don’t recall ever having trans temps creep out of the 130°s. I’m going to see how far the dash gauge is off from what’s coming from the computer to see if the numbers ever get to the 150°-160° range like you have noticed.

https://www.camaro6.com/forums/showthread.php?t=554779

I have no idea what the TCM is trying to do with these instantaneous pressure spikes. I don't think I've ever noticed any physical effects from them, either way I thought this TCC pressure was just a calculated inferred value? I thought the real pressure comes from what's diverted to the TCC circuit and then based on what the gain and offset of the TCC regulator.



I did the shudder fix about a year ago myself. I had the dealer do one of the first "triple flush" which didn't work and it came back, and then I drained the fluid and replaced it with about 12 quarts of the Mobil 1 LV synthetic which fixed the problem.

With the stock converter most of the time I think I remember it being in the 130 F range max like you said. I know to do the clean function and maybe the fast learn it has to be at least 150 F or so which I could get there by brake stalling it.

[Trochoidal]

SOB!! When I brought these spikes up you would’ve thought I posted seeing a monkey saddled up flying a pink unicorn. Damn, so you saw them too? Good to know I wasn’t alone. I’ve also never noticed anything physically coinciding with the spikes. So I left well enough alone and moved past researching.

150°!! When I did the flush it took every bit of 30 minutes or more to get to 130° to pull the plug to let excess drain. Your brake stall would sure take care of things.

I’ll watch this thread to see what comes of your converter and of course the main topic being whether you should pull the motor or trans.

[cmitchell17]

Just an update, the turbine shaft oring seal looked perfectly fine. I posted some pictures on my other thread. I don't know what I am going to do. I honestly just put the stock torque converter back in. I don't really care about a higher stall converter at this point especially if its going to rattle and make the car sound like a POS.

I guess the more times I pull the motor I should get good at it enough to where it shouldn't be that big of a deal anymore haha. But my hands are still killing me and it is still a lot of work and takes a lot of hours, even though when thinking of the steps in your head it doesn't seem that bad but there is always a PITA waiting around the corner.