flare shift cant figure out how to stop

[TransGo Robert]

TransGo Robert , would you mind posting up a screen shot of the bind you were seeing? Always intrigued me what to be looking for...

Sorry I got swamped this morning and just now was able to get to this. So here's a screenshot showing the bind with your previous tune. Now I have some math channels setup in there to calculates the precise ratios and the actual line pressure achieve in the unit so you won't see the same on your end if you graph the data so it would not be as obvious for you. You can see the bind when the yellow ratio graph line drops down to 1.472 then climbs back up and finally settle down to 1.53 like it should for third gear. I have put in read circles the points where you can see what is wrong and causing it. Bind 2-3.png

Next here's a screenshot of the 2-3 under almost the identical conditions after you modified your tune adn now you can see a nice gradual shift without a drop down in ratio below the 1.53 like it should for third gear. This time I put green circles around the same points where things are now commanded properly to achieve a nice clean 2-3 shift. Nice Shift 2-3.png

Hopefully this helps clarify things,

[GHuggins]

There's a tsb for this issue. Has to do something with air purging the clutch apply circuit for initial cold takeoffs causing a shift flare, but everyone I've ever seen with the problem has it more hot than cold. i know it comes up when googling 6l80 shift flare. Compare won't show anything changed. The corrections they make are in the background. I know there are several multipliers for the transmission controls in the background not to mention controls to cycle the solenoids after starting. SCT recently added the torque model multiplier from what I've been told. I've had to work torque models before to allow a hefty cam to idle without influence through the solenoid cycling before due to how an update caused it to load the clutches after initial startup. It caused it to idle dip on a genV. A good example of the multipliers is to compare a gen V 5.3 to a gen V 6.2. The 5.3 will have considerably more torque in the torque models even though we all know it doesn't make more than the 6.2l. The background multipliers are what offset everything. I'm just guessing, but I assume they changed the initial cycling to apply and bleed the clutch pack on startup especially since the update always seems to cause something after startup with idle.

The above posted is one I tuned the engine side and the customer got the tranny update done yesterday. He said there were 9 different updates for various problems. All in the background from the looks of it too. He's had a lot of work done to the tranny after a TCC came apart. He even had the carrier pinned and shift kits installed on top of the updated hub installed and was still having the 2-3 problem. He said it had it since it was new. Lowering shift times without lowering pressures just made his shift too hard due to all the other mods, so he went the update route and so far it's all fixed.

I was hoping to just be able to load a new one in for him as the dealer charged him nearly 300 just for the hour flash and learn, but I couldn't find one in my files with the update that was OS swap compatible and it's best to use TIS for the specific vehicle anyway.

[GHuggins]

Sorry I got swamped this morning and just now was able to get to this. So here's a screenshot showing the bind with your previous tune. Now I have some math channels setup in there to calculates the precise ratios and the actual line pressure achieve in the unit so you won't see the same on your end if you graph the data so it would not be as obvious for you. You can see the bind when the yellow ratio graph line drops down to 1.472 then climbs back up and finally settle down to 1.53 like it should for third gear. I have put in read circles the points where you can see what is wrong and causing it. Bind 2-3.png

Next here's a screenshot of the 2-3 under almost the identical conditions after you modified your tune adn now you can see a nice gradual shift without a drop down in ratio below the 1.53 like it should for third gear. This time I put green circles around the same points where things are now commanded properly to achieve a nice clean 2-3 shift. Nice Shift 2-3.png

Hopefully this helps clarify things,

So you're looking for up/down jumps or "hangs" then? Any chance you would share your maths?

[hjtrbo]

Robert, it sure does. Thanks very much

[TransGo Robert]

So you're looking for up/down jumps or "hangs" then? Any chance you would share your maths?

The math is simple just input RPM divided by output RPM in other words: [4110.56]/[4111.56]. You can see the problem just looking at the input sensor, but it is much easier with the ratio calculation specially when you are chasing a slip or a flare. It should never overshoot the ratio you are going into, when it does most of the time it is because of too much overlap like it was in this case.

[GHuggins]

I thought you also had one to get more accurate line pressure. That's my fault.

Thank You for showing what to look for. Now I'm going to have to bog my scanner down more

[TransGo Robert]

I thought you also had one to get more accurate line pressure. That's my fault.

Thank You for showing what to look for. Now I'm going to have to bog my scanner down more

Oh yea my bad, I forgot about that one. It is a bit more tricky and it works only for stock units, if the PR valve spring or boost valve has been replaced from one of our kits or someone else then the math will no longer be right. The formula is: 48+[4212.98]*2.18181818 so 48 plus PCS 1 commanded pressure times 2.18181818

[TheMechanic]

There's a tsb for this issue. Has to do something with air purging the clutch apply circuit for initial cold takeoffs causing a shift flare, but everyone I've ever seen with the problem has it more hot than cold. i know it comes up when googling 6l80 shift flare. Compare won't show anything changed. The corrections they make are in the background. I know there are several multipliers for the transmission controls in the background not to mention controls to cycle the solenoids after starting. SCT recently added the torque model multiplier from what I've been told. I've had to work torque models before to allow a hefty cam to idle without influence through the solenoid cycling before due to how an update caused it to load the clutches after initial startup. It caused it to idle dip on a genV. A good example of the multipliers is to compare a gen V 5.3 to a gen V 6.2. The 5.3 will have considerably more torque in the torque models even though we all know it doesn't make more than the 6.2l. The background multipliers are what offset everything. I'm just guessing, but I assume they changed the initial cycling to apply and bleed the clutch pack on startup especially since the update always seems to cause something after startup with idle.

The above posted is one I tuned the engine side and the customer got the tranny update done yesterday. He said there were 9 different updates for various problems. All in the background from the looks of it too. He's had a lot of work done to the tranny after a TCC came apart. He even had the carrier pinned and shift kits installed on top of the updated hub installed and was still having the 2-3 problem. He said it had it since it was new. Lowering shift times without lowering pressures just made his shift too hard due to all the other mods, so he went the update route and so far it's all fixed.

I was hoping to just be able to load a new one in for him as the dealer charged him nearly 300 just for the hour flash and learn, but I couldn't find one in my files with the update that was OS swap compatible and it's best to use TIS for the specific vehicle anyway.

Just looked it up and they have updated the bulletin to say it is normal. Ugh.Document ID_ 6159183.pdf

[GHuggins]

Just looked it up and they have updated the bulletin to say it is normal. Ugh.Document ID_ 6159183.pdf

Haha, typical right Guess they had some it wasn't completely fixing so they just covered their butts and released another one saying it's all good...

[TZTuning]

My issue was in my tune, I had it shifting good and couldn’t remember(find) what I did to mess it up, and had tried working backwards which wasn’t helping so I had to reach out for help.

[hjtrbo]

Looked like shift pressure was the big stand out

[hjtrbo]

I don't have output shaft speed (6L90). I've raised a support request. In the mean time I'm testing out using undriven wheel speed with a high polling rate. Works fine. For those in the same situation the formula is:

[4110.56]/([8001.113]/60*1000/2.2*3.23)

Replace 2.2 with your tyre circumference.
Replace 3.23 with your diff ratio.