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Thread: 6l80e swap killing motor in forward and reverse randomly. Anyone seen this happen?

  1. #1
    Advanced Tuner lt1z350's Avatar
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    6l80e swap killing motor in forward and reverse randomly. Anyone seen this happen?

    So just swapped my 07 nbs tahoe to a 6l80e. At first I used the old techem and was ok with random flares but the worst part was on start up it was randomly locking the converter soon as started fwd or reverse it would kill the motor. So put in a new techem programed a 2008 yukon os into it which and verified the engine os was correct to that tcm os. First new start up was fine drove better could tell needed the be quick learned or just drove more. Better engagement not lagging as was with old tcm and no lock up issues. Then this morning when going to work it started to lock up in reverse a little and pulled through it then ok. I do run the truck stock tune for the moment and using the dual disk zl1/ctsv converter. So wondering if maybe these settings are way different going to pull a 09 ctsv trans tune and look at the lock up stuff. I don?t know if it?s commanding it yet or it?s hydraulic apply I have yet to put the scanner and look at pid on it. I did build the trans what I do for a living. I did a sonnax upgrade to my pump that we do to all of them at work to help it not over pressure lockup and bend the guts in the converter one reason a lot of stock tc fail is from this issue. It?s a new torque converter but doesn?t mean isn?t not messing up. Just wanted to ask if anyone had run into this and what fixed it. We have never had this happen at work and build a ton of these trans.
    Thanks
    First 9 second 6th gen lt4 zl1 stock blower SHC SBE boost only.

    2013 cadillac ats 2.0t Big turbo-gone
    2007 tahoe 5.3 lsa blower on 14 lbs boost 6l80e swap 2009 os
    2017 zl1 a10 big gulp/2 inch headers/ 9.55 lower/ e85/bigger hx /103mm tb / Synergy trunk tank and underhood kit/methanol injection with torqbyte controller and prometh pump / Jokerz performance R&D ported stock blower/ lme cnc heads /GP tuning custom cam. So far 9.30@150

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    Have you posted up a tune?

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    tune

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    Advanced Tuner lt1z350's Avatar
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    I just pulled pan checked the tcm screens cleaned them put in a new filter and 7 quarts of dex 6. Did a solenoid clean and a quick learn on it. It now wont kill the motor on start up if I let it sit for about 30 seconds before I engage it. But now its locking up right after the 1-2 shift and keeps lock up as it up shifts. When it gets warm it goes away or if it makes a few up shifts. once it quits its fine until I key cycle and it cools off. Seems like its worse when I am commanding more pressure on the shifts. Starting to think its a cross leak in it somewhere. If I go back to a stock tune its not as bad. It might not even do it on stock tune now with the flush but shifts like crap and lazy so I have to fix this. Its not commanding it I do know that now. I have a sonnax zip kit in the valve body and I put the over sized pr valve in the pump. Going to get a gauge on it and see if pressure is low or normal. I do these at work and know this has to have enough pressure to keep it off as it does to keep it in lock up. I have followed the full power flow of the tcc release circuit and it is all in the stator and pump body fed to the input shaft and to the converter. So most likely a torque converter failing or a pump issues and cross bleed of some sort. I bought a core so dont know if this was a problem before the build. The new techem made it so I can at least drive it ok once temp is up so that helps. It would be nice if could change up something in the tune to fix it but so far seems I only make it worse. at least on the newest ctsv settings for lockup tables it will let me start up and go with out having to wait out over 100 degrees on it. Open for any ideas but looking like I need to have the dealership warranty out the converter and going to change up the whole pump just to be safe.
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    Last edited by lt1z350; 12-15-2018 at 07:49 PM.
    First 9 second 6th gen lt4 zl1 stock blower SHC SBE boost only.

    2013 cadillac ats 2.0t Big turbo-gone
    2007 tahoe 5.3 lsa blower on 14 lbs boost 6l80e swap 2009 os
    2017 zl1 a10 big gulp/2 inch headers/ 9.55 lower/ e85/bigger hx /103mm tb / Synergy trunk tank and underhood kit/methanol injection with torqbyte controller and prometh pump / Jokerz performance R&D ported stock blower/ lme cnc heads /GP tuning custom cam. So far 9.30@150

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    Did you change the shift pattern types, Tap-Up.Tap-Down parameters? I'm comparing your's to my STS-V file. as a test take all the apply lock-up speeds for all the patterns and make them 158 to see if it's still locking up. When you log what pattern does the trans say it's in?

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    I have had this happen. But for me it wasn't a tuning issue. Does this still happen if you unplug the transmission? If YES, How is cooler flow?

  7. #7
    Advanced Tuner lt1z350's Avatar
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    sorry guys been meaning to update this thread on what I found. SO it was worse when cold and if I let it run a bit didnt act up. So I starting thinking it was more hydraulic issue as the temp or viscosity of the fluid seemed to affect it. I put a gauge on it and was shocked. At rest in park it was around 200 psi and if I goosed it a little it well broke my 400 psi gauge. When iit got warm it would drop to about 175 and that was low enough to let me pull it into gear and then it was 90 psi but if i was to brake torque it a little it would go to 200 pretty easy. So I pulled it back out and found two things. One the pump slide was getting hung up. It was a machined bellhousing and my slide clearance was around 1 thousandths on one side and 1.5 when checked in another spot so I kept working around and found a spot that was around 1/2 that as that was where it was causing it to hang. So the shop that machined the pump rotor area didnt do a great job on making sure it was correct all the way around. So I got a new bell housing as didnt want more issues only 98 bucks from the dealership. Now new slide redid all the clearance and have it about 2-2.5 now. Also maybe a problem that was caused by the high line I found the o ring on the stator between pump body and stator was cut and blown out. I also had the shop machine the pump face and they reassembled the pump stator to the body so they most likely cut it.
    I have it all back together and now works good. No lock up issues other then this dual disk lsa tc was pulsing at speed and driving me nuts. The more pressure I put to the apply ramp table the worse it got. So I found an old thread on changing the regulartor settings from 26 psi to 50 or more and the gain to 1.0 and I went with 50 and 1 and it locks up like my old 4l60e I had that with a trans go lock up valve and it was fast and firm no modulation at all on that and now on this one the same way. I had tried everything to this point and that was the best adjustment for lockup by far. Now I can play with speed and gear to make it work for me. I did set the adapts up too so It couldnt learn down only up to 100 psi if it needed more.
    Now I got to get this shift timing better. I have firm shifts but they drag a little and I have gone very short on the timing down to 2.5 so far with zero adders in the other tables. I have left the torque management on and have it setup at 1.000 so that way its pulling some timiing on the shifts as this is a 5.3 in a 5800 lbs tahoe with 14 psi from an lsa blower and its making around 550whp so didnt want to have the trans taking a beating from the weight and instant torque of this blower. the shifts have a pop at the end but drag some what they arent very fast for how I have it so far. My other cars are 2017 zl1 and 10 speed and 16 ctsv sport with asian 8 speed and both of those shift fast stock so maybe Im being a little hard on the way the 6 speed is shifting. I thought about some virtual torque changes in the ecm side could help it too as I had gone back to stock on them as the 4l60e was slamming when I raised them too much so to make the old trans so wasnt beating me to death I changed all that back to stock. Maybe its just a timing thing up for any tips on it. Thanks for those that tried to help and hope my post can help anyone else that might have a lock up issue where stalls engine. Ill start a new thread on my shift concerns and read up some more on it.
    First 9 second 6th gen lt4 zl1 stock blower SHC SBE boost only.

    2013 cadillac ats 2.0t Big turbo-gone
    2007 tahoe 5.3 lsa blower on 14 lbs boost 6l80e swap 2009 os
    2017 zl1 a10 big gulp/2 inch headers/ 9.55 lower/ e85/bigger hx /103mm tb / Synergy trunk tank and underhood kit/methanol injection with torqbyte controller and prometh pump / Jokerz performance R&D ported stock blower/ lme cnc heads /GP tuning custom cam. So far 9.30@150

  8. #8
    Advanced Tuner lt1z350's Avatar
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    Just to close this out it was a pump issue causing the problem had zero to do with the tune and couldnt be tuned out.
    First 9 second 6th gen lt4 zl1 stock blower SHC SBE boost only.

    2013 cadillac ats 2.0t Big turbo-gone
    2007 tahoe 5.3 lsa blower on 14 lbs boost 6l80e swap 2009 os
    2017 zl1 a10 big gulp/2 inch headers/ 9.55 lower/ e85/bigger hx /103mm tb / Synergy trunk tank and underhood kit/methanol injection with torqbyte controller and prometh pump / Jokerz performance R&D ported stock blower/ lme cnc heads /GP tuning custom cam. So far 9.30@150