6l80 2-3 Bind

I havn't noticed much of an issue with this transmission after being rebuilt, but now since my fueling and TQ tables are more inline from the dyno, I am getting a 2-3 bind/tie-up. I did remove the wave plate in the 35R as per sonnax. So far the consensus is that the wave plate needs to be there.

Ive played with almost all the settings in HPT with no luck. Well I should say, I don't have the bind at first, then the trans "adapts" to a tie-up. Also, seems it binds the worst after it goes into discreet shifting and line pressure clamps around 84 PSI.

I can't believe there isnt a table/setting that could help the TCM adapt. Only thing left is the Output Torque Shift Factor, ive halved that table with no noticeable difference, I also don't fully understand how to relate the oncoming shift pressure and offset pressures over elapsed shift time, to that table. Im not paying much attention to the other shifts being it is all put back to stock for testing.

Eric

Short update, it definitely seems to be related to when discrete shift is active. I am going to raise the TQ threshold a little bit to keep it out of High Torque Discrete, to save the trans for now until I can figure out a way to calibrate for no wave plate.

I don't know enough about tuning to know how to go around the problem that way. But removing wave plates, adding frictions or reducing clutch pack clearances always cause headaches on those. Not to mention it is not needed in the first place. If you ever have to go back in the unit, do yourself a favor and put all the clutch packs back to stock and install our 6L80-TOW&PRO kit in it and you will be amazed how great it will work.

I made all the clearances to spec and used GM methods with the special tools. Thats why I am having a hard believing there isnt a way to compensate for no "cushion" in the apply through the calibration.

I might be going that route. How would the tow and pro work with an added pressure Boost valve?

Quote:

---

Originally Posted by ns158sl

I made all the clearances to spec and used GM methods with the special tools. Thats why I am having a hard believing there isnt a way to compensate for no "cushion" in the apply through the calibration.

I might be going that route. How would the tow and pro work with an added pressure Boost valve?

---

There is a way to go around the problem that removing the wave causes, I just don't know how it is done in the tuning, that's not my strong point. No need to raise pressure on those they already crack drums and pistons, we actually limit it with our kit. The changes are done hydraulically in the unit moifying the rate at which the pressure increases as well as when it goes from regulated clutch pressure to full clutch pressure no matter what the computer does.

Just thinking for your testing, perhaps keeping discrete enabled might help as its giving a repeatable pressure for you to judge other adjustments against. Saying that it gets worse in that mode, maybe the pressure for that threshold zone might need to come down a bit, which raises another question

With your torque tables, do you know how the numbers were generated?
I.e.
Matched up the rear wheel gear ratio corrected torque to engine torque PID or
Matched up the rear wheel gear ratio corrected torque plus drive line losses to engine torque PID

Quote:

---

Originally Posted by TransGo Robert

There is a way to go around the problem that removing the wave causes, I just don't know how it is done in the tuning.

---

What is the gist of what needs to happen? Might be able to work it out between us.

I used the dynos calculated engine torque connected to the pro link. I'm not positive how accurate it is, but I figured it's closer than guessing lol. The little information I do have is it does factor in flywheel inertia, roller inertia, trans gear ratio, drivetrain ratio, drivetrain losses.

It seems discrete is for the adaptives to learn, but for some reason when it goes into High Torque discrete, it never "learns" correctly at 82 psi line pressure.

Quote:

---

Originally Posted by hjtrbo

What is the gist of what needs to happen? Might be able to work it out between us.

---

The command for PCS 2 needs to change so that the 3-5 clutch it controls does not start to apply so quickly. It is applying during the fill phase of the shift (see attached graphs showing the 4 phases of the command for an oncoming elements). This phase is only supposed to fill the hydraulic circuit for that clutch without applying it. But once you remove the wave that is normally absorbing this pulse to fill the circuit it manages to start applying the clutch, and since the 2-6 has not started to release yet, you get the bind. So if you look at the two screenshot I am attaching of the OP's log you can see the bind in the red circle I added and the fill phase command in the read box I adeed. One is zoomed out where it is easier to see the bind, the other one is zoomed in more so that you can see better how the computer is controlling each phases of that shift. So what you need to change is how high the solenoid output pressure command is during the fill phase. I have no idea how it is done, but I know it can be done because the bind up when people remove waves or reduce clutch pack clearances is a very common issue, and many times the transmission techs will say "my tuner fixed it".
Attachment 145844
Attachment 145845
Attachment 145846

Curious what vehicle is this out of?
I don't understand the details, but have noticed these differences on the tuning side.

'15+ have no adder modifiers. And 1-2 and 5-6 volume presets halved, extra disc (6l90?) or someother change?
'15+ desired torque ouput 1-2 has positive and negative numbers, '12 model only had negative numbers
'18+ desired torque ouput factor tables zero'd for 1-2 and 2-3 shift.
Also the '18 tune has 2-3 offgoing pressure reduced a little..

I tend to like the 18+ settings simply because less tables are used!

If anyone has basic explanation of desired output torque factor, adder modifier map, and transition times... I'm all ears.

This is exactly what I seen. There is a guy from SIU that put in pressure taps and recorded everything happening. My problem is I can't find a way to reduce the fill phase through HPT. There are presets, but the adapts just take over that after driving.

Quote:

---

Originally Posted by ns158sl

This is exactly what I seen. There is a guy from SIU that put in pressure taps and recorded everything happening. My problem is I can't find a way to reduce the fill phase through HPT. There are presets, but the adapts just take over that after driving.

---

Yea Sean Boyle does a great job as usual explaining each phases of the shift and it was quite interesting to follow along as he was doing all the testing. I will let others that know about tuning give you advice, but I can't help but wonder if you could not simply solve your issue by disabling the adapts?

Quote:

---

Originally Posted by mikez71

Curious what vehicle is this out of?

---

2012 Yukon

There is a few knobs to be turned. It appears from all my internet searching the fix is not public. I have a significant dis-taste for people hiding information, just small cock bull shit if you ask me.

ns158sl I have no idea to be frank, but here is a screenshot anyway.

My thought process is;

• Reset the adapts. You'll only get a small window to where it's adapted away from the initial settings. I imagine after every change whilst testing you would reset the adapts again.
• Clamp the fill volumes for 2-3. Raise or lower to find the 'kiss' point. To high it'll bind, to low it'll flare.
• Pressure presets, thinking leave alone whilst you're adjusting volume. We must only turn 1 knob at a time. Pressure and time would be proportional to volume I think.
• Discrete shift torque. I'd be inclined to leave that alone as its giving you consistent shift pressure to evaluate the changes
• Ideally a load bearing dyno so trans torque can be kept constant for back to back comparisons.

I have no idea but goodness me, ns158sl if you're willing, there will be some good data to look at.

https://i.imgur.com/Ct7etX7.png

Why not lower the adapts and fills for the clutch having problems? Don't know if these are anywhere near right, so ease up to what you're testing for throttle wise to make sure it's not going to slip. Goal is to apply enough to bleed air without applying the clutch. I'm not a fan of removing the waves. They're there for more than just cushioning the shift. They're also used to separate the clutch for the next application. You can wind up causing problems with them gone from a clutch not disengaging quick enough just as easily with them being there for other reasons only things are easier to set up with them there.

Quote:

---

Originally Posted by hjtrbo

There is a few knobs to be turned. It appears from all my internet searching the fix is not public. I have a significant dis-taste for people hiding information, just small cock bull shit if you ask me.

ns158sl I have no idea to be frank, but here is a screenshot anyway.

My thought process is;

• Reset the adapts. You'll only get a small window to where it's adapted away from the initial settings. I imagine after every change whilst testing you would reset the adapts again.
• Clamp the fill volumes for 2-3. Raise or lower to find the 'kiss' point. To high it'll bind, to low it'll flare.
• Pressure presets, thinking leave alone whilst you're adjusting volume. We must only turn 1 knob at a time. Pressure and time would be proportional to volume I think.
• Discrete shift torque. I'd be inclined to leave that alone as its giving you consistent shift pressure to evaluate the changes
• Ideally a load bearing dyno so trans torque can be kept constant for back to back comparisons.

I have no idea but goodness me, ns158sl if you're willing, there will be some good data to look at.

https://i.imgur.com/Ct7etX7.png

---

I was apparently making changes when you posted this :) Don't forget the pressure presets too... Again, I don't know if what I posted is near right. Every one of these acts different depending on the build.

Well i appreciate all the info. I can get it on the Dyno here in a few days so I might as well wait until then to make changes.

ns158sl are you all over discrete shift torque? Happy to go over it if needed.

Quote:

---

Why not lower the adapts and fills for the clutch having problems?

---

because that is just presets. The algorithm is going to learn what "it" wants. I have tried that and found the outcome the same.\

Quote:

---

all over discrete shift torque?

---

Not sure. I have a bit to clean up yet, but I will put this thing back on the dyno for testing.

Quote:

---

Originally Posted by ns158sl

Not sure. I have a bit to clean up yet, but I will put this thing back on the dyno for testing.

---

Was meaning if you needed an explanation on how it worked.

I would appreciate an explanation hjtrbo!

Would also love to know why my graphs for PCS pressures and TCC slip/pressures are basically spikey straight lines and not detailed like the everyone else's graphs?
(polling intervals were 0, and now 10ms as I can't select 0ms...) What am I doing wrong?

Quote:

---

Was meaning if you needed an explanation on how it worked.

---

By all means!

I read Chris's explanation on an older thread, my understanding was for the ECM to keep a constant line pressure to self calibrate apply/release pressures? I also ASSume it ramps line depending on torque, either A: to prevent slipping being it is in a way "open loop" and B: Theoretical required line pressure for added torque.

It almost seems people spend so much time playing with the presets, but in actuality it is just a "start" for the adapts to take off from there. It really is shift times and clamp pressure is key to an adapted shift. I should be able to do some testing in a few days yet. I was hesitant of clamping adaptives, only because it is a daily driver. But will definitely go ahead for testing purposes.

Thanks again!

Quote:

---

Originally Posted by mikez71

I would appreciate an explanation hjtrbo!

Would also love to know why my graphs for PCS pressures and TCC slip/pressures are basically spikey straight lines and not detailed like the everyone else's graphs?
(polling intervals were 0, and now 10ms as I can't select 0ms...) What am I doing wrong?

---

Can you take a screenshot of the "spiky straight lines" you are talking about, and attach it here, so that I can see and understand better what you mean. On my end looking at your log, the PIDs you mentioned graph nicely like any other ones I have ever looked at.

Quote:

---

Would also love to know why my graphs for PCS pressures and TCC slip/pressures are basically spikey straight lines and not detailed like the everyone else's graphs?

---

I found one of your logs, that definitely seems like a polling interval issue/scanner issue. For a test, log only the 5 pressures at fastest available to choose. Maybe someone here knows or it is worth contacting support.

Thank you both, don't mean to de-rail your thread!

Yep, seems like my TPS/RPM's are fine, but lots of charts spikey. I did remove a couple channels, slowed down the polling interval on others. No change.

Attachment 145877

Will do one with just a few pressures as suggested to test...
(I did open a support ticket for my missing OSS signal, the graph section lets me choose transfercase output speed, but it is not listed in the channels I can log.. )

Quote:

---

Originally Posted by mikez71

Thank you both, don't mean to de-rail your thread!

Yep, seems like my TPS/RPM's are fine, but lots of charts spikey. I did remove a couple channels, slowed down the polling interval on others. No change.

Attachment 145877

Will do one with just a few pressures as suggested to test...
(I did open a support ticket for my missing OSS signal, the graph section lets me choose transfercase output speed, but it is not listed in the channels I can log.. )

---

Oh I did not realized you were not the OP! Now I see what you mean. I have no idea why the polling is so slow in yours, I would open a support ticket if it was me or start a new post of your own with your log attached asking for help with this problem.

UPDATE: I'm an idiot, logging in standalone mode before. Hooked up a computer and it's looking good! Still no OSS, that's another thread.

Thank you, and please continue hjtrbo, Rob, and ns158sl!

Actual torque (aka engine torque or trans torque etc.) is your x axis. It has 2 break points which define 3 zones. The y axis is a constant torque 'number' the trans will use as it's lookup value to the shift pressure table. The y axis value is determined by which x axis zone you're in.

E.g at 100 degC TOT.
x = 100Nm, y = Low -> Shift pressure lookup torque = 0Nm -> Shift pressure = 504kPa
x = 350Nm, y = Mid -> Shift pressure lookup torque = 300Nm -> Shift pressure = 800kPa
x = 450Nm, y = Hgh -> Shift pressure lookup torque = 600Nm -> Shift pressure = 1472Nm

https://i.imgur.com/sD7iHsA.png

This confirms what I was thinking. Someday I might learn your screenshot skills, but I doubt it, lol.

I still stand at the TCM doesnt know how to adapt when the line pressure is high.

There must be an adjustment for fill time, by rights a fast learn/long term adapts will learn pressure. Without any clue of getting a BIN/XDF, I don't think HPT support is going to go diving in this OS for that.

Thanks for that hjtrbo!

As a tuner, I HATE when wave plates are removed. Some trans builders will do things like remove wave plates, add clutches, etc, without explaining the pros and cons to the customer. So here we are, left to explain why you can't truly achieve a buttery smooth shift under part throttle after the tuning is complete.

Yeah I never did that with 4 speeds, I figured there was a way to tune for it with a CTC. For my personal experience I won't be doing this again, but I want to figure out how to work with these transmission issues in the future.

Alright I finally got around to testing. I would reset adapts and reset presets each time after flash KOEO. I then let it idle in drive off the brake for a couple min before recording. I havent had time to review the logs other than watching it real time during testing, I will be reviewing them later tonight. I only posted one Cal file being you can look at history of changes, which was only those three tables. I can post the other logs from 15 to 25 if needed.

Quote:

---

Originally Posted by ns158sl

Alright I finally got around to testing. I would reset adapts and reset presets each time after flash KOEO. I then let it idle in drive off the brake for a couple min before recording. I havent had time to review the logs other than watching it real time during testing, I will be reviewing them later tonight. I only posted one Cal file being you can look at history of changes, which was only those three tables. I can post the other logs from 15 to 25 if needed.

---

The 2-3 shift looks great now on the last one.

Thanks for posting your results. Awesome work man.

So you made min, max and oncoming all the same and then raised off-going to allow more disengagement time? Nice... Did you just find that having all the presets the same made it easier to set things or it just keeps it from shifting the adapts around better?

Was there a reason for the drastic torque model changes?

Well this test was mostly for testing purposes/data along the lines of what Hjtrbo was saying. So I now I have to use that data to fix this, lol. Appears to still be in the low breakpoint for discrete shift pressure.

The tq tables are a work in progress, well I am still working on it today. Those were pretty hacked yet compared to today.

I locked out the adapts to just see what volume affects. Seems like it does affect the fill phase time. Vehichle is still strapped down, but I will go for a drive here sometime this week. I settled on 27 for Volume and opened the adapts a little bit to see what happens.

I still am ASSuming if this doesnt work, there has to be somewhere in the TCM that compensates for the cushion/wave plate. Cat powershifts have been CTC for 30 plus years with no waveplates, lol. I know its a little different animal, but still.

Quote:

---

Originally Posted by ns158sl

Well this test was mostly for testing purposes/data along the lines of what Hjtrbo was saying. So I now I have to use that data to fix this, lol. Appears to still be in the low breakpoint for discrete shift pressure.

The tq tables are a work in progress, well I am still working on it today. Those were pretty hacked yet compared to today.

---

Your original torque models were really close to what I would expect to see with a cam. Even close to how GM calculated them out for their bigger cammed crate motors.

Quote:

---

Originally Posted by ns158sl

I locked out the adapts to just see what volume affects. Seems like it does affect the fill phase time. Vehichle is still strapped down, but I will go for a drive here sometime this week. I settled on 27 for Volume and opened the adapts a little bit to see what happens.

I still am ASSuming if this doesnt work, there has to be somewhere in the TCM that compensates for the cushion/wave plate. Cat powershifts have been CTC for 30 plus years with no waveplates, lol. I know its a little different animal, but still.

---

From the looks of your VE, do you have a GPI stage 1?