GM 6L80 Transmission Information Thread

Geotrash · Nov 18, 2024

Foggy said:
New Question for Nick or Robert (transgo)
I am thinking of relocating my trans external fan forced cooler (for a couple of
reasons). I see that ICT billet has a nice adapter that mounts to my 6l80e
and I can just use only AN lines - my preference.
They make it in a 6an and 8an..
My question is there any advantage or disadvantage to go with the larger 8an
lines from trans to radiator to ext cooler then back to trans ??????
IDK if that changes pressures that would affect anything.. I would think the larger line
would flow a little bit more volume is why I ask.
Right now I'm running the factory steel lines in and out of trans case... with #6 lines
between radiator & ext cooler.
My mods are in signature

I don't know the answer off-hand, but you should be able to easily calculate that based on the ID of the smallest points in the system. The only thing the larger lines would potentially do is 1/ reduce the frictional losses within the hoses, but that's only a tiny fraction compared to any choke points in the fittings and ports on either end of each line, and 2/ give you larger and less restrictive fittings on the hose ends. But if the ID of the fittings at the radiator, at the external cooler, or at the transmission, are smaller than the larger AN hoses and fittings, the larger size AN won't really matter.

Foggy · Nov 19, 2024

Geotrash said:
I don't know the answer off-hand, but you should be able to easily calculate that based on the ID of the smallest points in the system. The only thing the larger lines would potentially do is 1/ reduce the frictional losses within the hoses, but that's only a tiny fraction compared to any choke points in the fittings and ports on either end of each line, and 2/ give you larger and less restrictive fittings on the hose ends. But if the ID of the fittings at the radiator, at the external cooler, or at the transmission, are smaller than the larger AN hoses and fittings, the larger size AN won't really matter.

I was kinda thinking the same thing... I've done several fuel system projects and
that's kinda the case - except you can just crank up the pressure at the pump and/or
regulate it with external regulator.. So bigger is better IF you need "flow"
Always appreciate your feedback !!!

Anyone else want to chime in ???

CTX-SLPR · Nov 20, 2024

CTX-SLPR said:
Drove it for around 30min with the gauge under the wiper, max temp was 189 on the DIC which matched the TECHM sensor value when I had a scan tool on it. Now I have done the HPTuners changes to pressures, slips, and a bit of turning on the 2-1 and 3-1 shift timings so I'm not strictly the same as stock anymore.

Out of gear idle: ~75psi
In gear idle: started at ~75psi but as it got warmer it dropped to 60psi

Driving around it was around 90psi with spikes to 120-160psi during shifts or as high 210psi if I got on it

The gauge seemed very responsive like the TECHM was commanding different pressure for upshifts, downshifts, and lockup and the regulator/controller was responding. I did see a few brief pressure drops on downshifts but things felt normal. I have some videos but it won't let me upload them.

Does anyone one else have HPTuners 6L80 mods and a pressure gauge to check what kind of behavior they are seeing? I’m leaning towards just putting the ZIP kit in and driving it to see what happens. Worst case I have to pull the whole trans out and I’m just out whatever trans fluid I spill around the clean catch basin (fluid has less than 1500mi on it) assuming I don’t find any new bits in the pan.

NickTransmissions · Nov 29, 2024

Bumping this thread with my latest 6L80 video series, this one a high performance build featuring a Circle D Transmissions Level 2 kit and Sonnax billet 4-5-6 hub/intermediate shaft.

Smolski · Dec 6, 2024

Nick,
thanks to your videos I was able to rebuild the gearbox. The gearbox was already rebuilt and someone put it together wrong, i.e. the freewheel was wrongly inserted.

For rebuilding I used Raybestos stage 1 friction and steel clutch kit and sonnax zipkit.
The converter was remanufactured that a reinforced Kevlar disc, only such a possibility I found in my country.

and now 3 questions to which I can not find answers:
1. there are 2 vent hoses attached to the bolt that connects the transmission to the engine, the first one is from the transmission and transfer case unfortunately I do not remember what the second hose is from. I would ask for a hint where to connect it
2.After the rebuild I should do a fast learning of the gearbox but I don't have this option in the scanner. I am using vxdiag nano and tech2win. Do I have to perform this learning? if so is there another way to perform it?
3.At about 35 mph the transmission goes into a strange vibration that only occurs around this speed and has to do with shifting. I suspect that at this speed the transmission engages 2 gears at once. Could this be a problem that the transmission has not yet learned to work properly after the rebuild or maybe I have put something wrong?

Tahoe14 · Dec 7, 2024

@NickTransmissions

NickTransmissions · Dec 7, 2024

Smolski said:
Nick,
thanks to your videos I was able to rebuild the gearbox. The gearbox was already rebuilt and someone put it together wrong, i.e. the freewheel was wrongly inserted.

For rebuilding I used Raybestos stage 1 friction and steel clutch kit and sonnax zipkit.
The converter was remanufactured that a reinforced Kevlar disc, only such a possibility I found in my country.

and now 3 questions to which I can not find answers:
1. there are 2 vent hoses attached to the bolt that connects the transmission to the engine, the first one is from the transmission and transfer case unfortunately I do not remember what the second hose is from. I would ask for a hint where to connect it
2.After the rebuild I should do a fast learning of the gearbox but I don't have this option in the scanner. I am using vxdiag nano and tech2win. Do I have to perform this learning? if so is there another way to perform it?
3.At about 35 mph the transmission goes into a strange vibration that only occurs around this speed and has to do with shifting. I suspect that at this speed the transmission engages 2 gears at once. Could this be a problem that the transmission has not yet learned to work properly after the rebuild or maybe I have put something wrong?

You're welcome, Smolski. What is a 'freewheel'? Are you referring to the rear sprag or something else?

The Stage One kit is a good kit and Zip kit is my 'go-to' for those transmissions so good on the parts selection. Yes, you need to complete a fast-relearn if you reused your TEHCM...You would need to program the TEHCM if bought new from General Motors or Sonnax. Not sure if Tech2Win works on anything beyond 2013 model years (the hand-held TECH2s do not) but you can purchase a subscription through AC Delco's TDS (Technical Delivery Service) and do your programming or fast adapts via TDS using the correct interface cable with your laptop. Can't speak to the hoses.

What were your clearances in all of the clutch packs (they are shown below)?

Low Reverse
2-6
4-5-6
3-5-R
1-2-3-4

Smolski · Dec 7, 2024

@NickTransmissions
“freewheel" - Low Reverse Sprag Assembly

I used an old TEHCM, the tech2win kit I have connects to it without a problem and I have the ability to read the parameters and test the gearbox. The only option in tech2win that I have is “Reset transmission adepts”.
I did not write down the clutch kit clearances values but they were within the values listed below. These came from the ASTG 6l80 book according to which I assembled the transmission.
Clutch kit clearances:
low/reverse - .050”
2-6 - .050”
4-5-6 - .050” - .074”
3-5-R - .048” - .070”
1-2-3-4 - .060” - .078”

NickTransmissions · Dec 7, 2024

Smolski said:
@NickTransmissions
“freewheel" - Low Reverse Sprag Assembly

I used an old TEHCM, the tech2win kit I have connects to it without a problem and I have the ability to read the parameters and test the gearbox. The only option in tech2win that I have is “Reset transmission adepts”.
I did not write down the clutch kit clearances values but they were within the values listed below. These came from the ASTG 6l80 book according to which I assembled the transmission.
Clutch kit clearances:
low/reverse - .050”
2-6 - .050”
4-5-6 - .050” - .074”
3-5-R - .048” - .070”
1-2-3-4 - .060” - .078”

Always keep track of clearances, end play measurements and anything similar as it's a record for what exactly you did to aid in trouble shooting...Mentioning this for anyone else reading that may or may not be aware of how important that sort of data tracking is when it comes to rebuilding transmissions, engines and anything else like-kind. Your third symptom sounds like an overly tight 4-5-6 clutch to me but it could be any number of things, including the TEHCM simply trying to adapt to what it's seeing...Hence why doing the fast adapt helps normalize the control logic and makes getting the transmission back to normal function much faster vs having the TEHCM do it on its own.

Reset Transmission Adapts is the function option you want to select to do the relearn...Click the 'Installation Instructions' link on the first page/post of this thread for step by step instructions on doing the relearn, if you need them.

CTX-SLPR · Dec 15, 2024

Emailed Sonnax about the use of just the valve body side of the ZIP Kit; the answer is yes as the rest of the parts are intended to compensate for wear in the pump which I don't seem to have after watching the pressures.

Dropped the TECHM + VB complex today and tore it down to inspect all of the spools, retainers, etc. What I found was all great except in one area... I have a late 2nd pattern separator plate but the rebuilder had left out the 8th check ball which is directly against the Sonnax instructions.

I don't know what this circuit does but could be the root of some of the wierdness I've been having.

I kept going with the kit and just need to get an inch-pound torque wrench and some DEX VI tomorrow. I debated reusing the 3mth old stuff which I caught in a clean container but now is not the time to cheap out.

GM 6L80 Transmission Information Thread

Geotrash

Dave

Foggy

Full Access Member

CTX-SLPR

Member

NickTransmissions

Sin City

Smolski

TYF Newbie

Tahoe14

Full Access Member

NickTransmissions

Sin City

Smolski

TYF Newbie

NickTransmissions

Sin City

CTX-SLPR

Member

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