DemonicDonut
TYF Newbie
- Joined
- May 15, 2023
- Posts
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Hello all, I'm hoping one of you wizards can save my bacon.
2010 Yukon SLT 5.3 LMG
I recently did a rebuild on my 6l80. New torque converter (local TC shop, billet and high carbon clutch), sonnax zip kit, transgo shift kit, transgo unbreakable ring kit, sonnax slide pivot pin, new bell housing, pump stator, tehcm seals and diaphragms, pioneer rebuild kit (all but steels)
I didn't disassemble clutch drums as I don't have a good press to reassemble, so I didn't replace the seals on them. I air tested all pistons but maybe I didn't don't right?
I'm having an issue intermittently with 4th gear.
When shifting into 4th under low load (~30pct throttle) the shift will attempt but flare and go back down and repeat until the CEL comes on and P1751 - shift valve performance code is in the trans. I have what seems to be called "busy shifting"
I have a HP tuner MPVI3 and have some logs I can attach soon that I recorded when the issue was happening.
When it does the flare, I can let off of it and sometimes it will shift but the shift time is very high (1 second or more)
It will also do this when in 5th and downshifting into 4th with light throttle.
I've played with TCC lockup and shift pressures, which seems to have helped but it's still happening at times.
I've pulled the tehcm and valve body off. Opened it up, cleaned everything really well and made sure everything was assembled correctly, check balls in place etc. I used the correct gasket for my valve body year.
I didn't ohm the solenoids though, which I'm kicking myself for now.
The main weird thing is the intermittent aspect. It was bad and I adjusted pressures and it seemed to be resolved for over a week. We towed our TT to the beach and it did the busy shift 1 time out of 4 hours of driving on the way there. I adjusted oncoming and off going pressures slightly as well as shift pressures (slightly increased low load section of tables) and on the way home it never had a problem.
The next day it did it to my wife and I played with programming again, it drove fine for me afterwards and now it happened to her again.
I'm at a loss for what it could be, unless the adaptives are taking too much pressure out of the 3-4 and 5-4 shifts over time. But towing was perfect?
Is there something in the programming I need to change with the new TC or parts I changed out?
Any help would be great. Feel free to ask questions. I'm working but have a slow day and will check here throughout the day. I'll be adding the logs as soon as I can.
Thanks for the help.
2010 Yukon SLT 5.3 LMG
I recently did a rebuild on my 6l80. New torque converter (local TC shop, billet and high carbon clutch), sonnax zip kit, transgo shift kit, transgo unbreakable ring kit, sonnax slide pivot pin, new bell housing, pump stator, tehcm seals and diaphragms, pioneer rebuild kit (all but steels)
I didn't disassemble clutch drums as I don't have a good press to reassemble, so I didn't replace the seals on them. I air tested all pistons but maybe I didn't don't right?
I'm having an issue intermittently with 4th gear.
When shifting into 4th under low load (~30pct throttle) the shift will attempt but flare and go back down and repeat until the CEL comes on and P1751 - shift valve performance code is in the trans. I have what seems to be called "busy shifting"
I have a HP tuner MPVI3 and have some logs I can attach soon that I recorded when the issue was happening.
When it does the flare, I can let off of it and sometimes it will shift but the shift time is very high (1 second or more)
It will also do this when in 5th and downshifting into 4th with light throttle.
I've played with TCC lockup and shift pressures, which seems to have helped but it's still happening at times.
I've pulled the tehcm and valve body off. Opened it up, cleaned everything really well and made sure everything was assembled correctly, check balls in place etc. I used the correct gasket for my valve body year.
I didn't ohm the solenoids though, which I'm kicking myself for now.
The main weird thing is the intermittent aspect. It was bad and I adjusted pressures and it seemed to be resolved for over a week. We towed our TT to the beach and it did the busy shift 1 time out of 4 hours of driving on the way there. I adjusted oncoming and off going pressures slightly as well as shift pressures (slightly increased low load section of tables) and on the way home it never had a problem.
The next day it did it to my wife and I played with programming again, it drove fine for me afterwards and now it happened to her again.
I'm at a loss for what it could be, unless the adaptives are taking too much pressure out of the 3-4 and 5-4 shifts over time. But towing was perfect?
Is there something in the programming I need to change with the new TC or parts I changed out?
Any help would be great. Feel free to ask questions. I'm working but have a slow day and will check here throughout the day. I'll be adding the logs as soon as I can.
Thanks for the help.
