6L80E TCC info

[Waker]

Thought I would share some research on this TCC/TCM. So far I've been able to determine with HP and another software that PWM is disabled in this tranny. Having said that, I believe the TCC solenoid regulates line pressure based on estimated engine torque. I say PWM is disabled based on the code in the TCM and the lack of a PWM solenoid in the schematic I have. We have found some TCC desired slip tables that are RPM based. I think these tables could play a role in why I don't see max line pressure after lockup. If you monitor the log, you can see TCC pressure rise as TPS increases. I can force lockup with the scanner and get 594psi displayed along with a very aggressive engagement of the TCC. Under a normal WOT run to 120mph the TCC engages in second gear and the pressure reads about 30psi. The pressure gradually rises throughout the run and reads about 104 at the end. TCC slip is around 100rpm until midway through third where is drops to zero and stays there. What is interesting is when I force lockup in second I get 594psi and the TCC slip goes to zero. This clearly shows how tight the stock converter is. I have also run a log with no TCC lock up. The average TCC slip during a WOT run is a little over 100rpm with no TCC line pressure. I think if HP could get us the desired slip tables and more control over TCC line pressure we could make better use of aftermarket converters. If we were to have access to the desired slip tables I believe we could even program in a stall Bill, Chris?? Forgot to mention I see no PWM duty cycle while logging, another reason I feel it does not exist on the tranny.

[parish8]

if it doesn't have pwm then how does the reported tcc pressure change? it isn't just on or off so there must be some kind of varied aplication.

[madvette08]

The TCC apply pressure is based on RPM slip and delivered engine torque. The TCM while in lock-up tries to control slippage of the clutch plate and the converter cover to between 0-80 rpms.

The TCM looks at input rpm and turbine rpm to determine slippage.

Ian

[Waker]

if it doesn't have PWM then how does the reported TCC pressure change? it isn't just on or off so there must be some kind of varied application.

Thats where the desired slip tables come in. The TCM regulates TCC line pressure to achieve desired slip. Vince is going to map these tables over the next few days. He and I both believe they are the key to achieving zero slip at any RPM.

[parish8]

right, it regulates tcc line pressure. probabbly by pulse width modulation to the pressure valve. if not then it controls current to that valve.

[Waker]

right, it regulates TCC line pressure. probably by pulse width modulation to the pressure valve. if not then it controls current to that valve.

Your guess is as good as mine. If we could see what type of signal is being sent through VCM scanner for lockup, maybe that would help. Engineers?

[madvette08]

right, it regulates tcc line pressure. probabbly by pulse width modulation to the pressure valve. if not then it controls current to that valve.

The Electronic pressure regulator (TCC PCS) is controlled by current flow to the solenoid to control apply and release. The TCC PCS requlates actuator feed limit fluid pressure to the TCC requlator valve, located in the lower valve body and provides a signal pressure to shift the TCC control valve, located in the pump to the apply position.

Hope that helps.

Ian

[Waker]

The Electronic pressure regulator (TCC PCS) is controlled by current flow to the solenoid to control apply and release. The TCC PCS requlates actuator feed limit fluid pressure to the TCC requlator valve, located in the lower valve body and provides a signal pressure to shift the TCC control valve, located in the pump to the apply position.

Hope that helps.

Ian

More information than we had...Now we just need control of it

[Waker]

"I did find six tables that appear to be related to TCC Desired Slip rate, one of the axes being turbine RPM – the other axis I’m still working on, but they have fairly high values in them – 1240 RPM, for instance, so maybe they are maximum thresholds or something.



The thing is, though, it seems like it applies the smallest amount of TCC PCS possible to achieve the desired slip, so even if desired slip is zero (and it’s trying to hit exactly zero), it would probably apply the smallest amount of pressure to get there."



Yeterday

[camaro1]

from the gm service manual:

A torque converter with an electronically controlled capacity clutch (ECCC). ECCC was developed to reduce the possibility of noise, vibration, or chuggle caused by TCC apply. In a torque converter with ECCC, the pressure plate does not always fully lock to the torque converter cover. Instead, the pressure plate maintains a small amount of slippage. In RWD 6-Speed transmissions, this slippage can range from 0-50 RPM. Full lockup (0 RPM slip) is still available on some applications. TCC may apply in 2nd, 3rd, 4th, 5th, or 6th gears. The specific TCC apply points and the amount of clutch slippage are determined by a number of operating conditions, including throttle position, vehicle speed, gear, as well as specific vehicle application. Transmission fluid temperature will also affect TCC apply points.


the key might be in some other tcm files from trucks or other 6l80/90e trans that still have full tcc apply.

[Waker]

" Well, so far as I can tell the maximum allowed TCC PCS is 109psi (758 kPa). This appears to be the final clamp on the TCC PCS. I’m not sure if the transmission can mechanically support a higher pressure here, or not. In fact, all of the PCSes seem to be capped at 109psi "

Parish, if your still slipping even when you force lockup, I don't believe your particular HP application can be helped. What could be done and probably needs to be done is for someone to make a converter that only needs 109 psi to hold 1000HP. I bet the guys at CircleD could come up with something. It's a simple matter of changing the piston type/size in the verter. Now for the rest of us not runing 600HP, I think we are on to something.

[Waker]

It makes sense then about the apply ramp table HP has given us. It is merely a way to adjust the rate of application from the PCS, not the PCS psi itself.

[parish8]

" Well, so far as I can tell the maximum allowed TCC PCS is 109psi (758 kPa). This appears to be the final clamp on the TCC PCS. I’m not sure if the transmission can mechanically support a higher pressure here, or not. In fact, all of the PCSes seem to be capped at 109psi "

Parish, if your still slipping even when you force lockup, I don't believe your particular HP application can be helped. What could be done and probably needs to be done is for someone to make a converter that only needs 109 psi to hold 1000HP. I bet the guys at CircleD could come up with something. It's a simple matter of changing the piston type/size in the verter. Now for the rest of us not runing 600HP, I think we are on to something.

that 109psi is not an actual pressure measurement. the actual line pressure is 2-3 times what the pcs1 is comanding.

when i force lock up with the scan tool my actual main line pressure is under 100psi. that is when it slips. i would bet if the main line pressure was in the 200psi range it wouldn't slip.

[Waker]

What is being said is the PCS is only capable of handling 109psi no matter what line pressure you have set.

[parish8]

What is being said is the PCS is only capable of handling 109psi no matter what line pressure you have set.

pcs1 may only show 109psi max but the actual pressure is much higher. here is a log showing pcs1 and ACTUAL line pressure.


http://www.hptuners.com/forum/attach...1&d=1270768342

[Waker]

Is PCS1 the TCC PSC?

[parish8]

no, it is the main line pressure pcs. you see how the pcs1 pattern matchs the actual line pressure. that is other than 1st gear wich is kind of scarry. i see low line pressure and slip in 1st gear even though the pcs1 is asking for high pressure.

[Waker]

Can you post your most recent tune?

[Waker]

We can change the 109.9 limit on the TCC solenoid. On another note I just ran a log in Tulsa 1K DA and showed 109.9 on the TCC line pressure at WOT from the bottom of third on. Which leads me to believe estimated engine torque is playing a role in lockup.

[parish8]

hey waker, i might be bailing from the whole 6l80e deal. between having to pull so much power at the shifts, the long shift times, the converter control issues, the line pressure issues and now what appears to be a loss of pressure and slip off the line i am considering doing a 4l80e swap.

i can get a 4l80e for $800, shift kit for $100, make a controler for probably $300 or so. might need to have my converter reworked to work but the circle D guys are cool and would probably give me a decent deal, driveshaft wich i need anyways. all total under $2k i bet for a set up that would be good for a 9sec power and is buildable to hande really crazy hp. really crazy hp is where i might be headed eventualy so the swap is worth considering.

about the slip off the line. did you look at that screen shot above? i got that every run last night and the harder i tried to launch the worse it got. line pressure down around 50psi, considerable slip, loss of aceleration, then grab and wheel hop. that cant be good for anything.