CTX-SLPR
Member
Nick,
Any recommendations for where to get one or just take the chance of buying the new parts and just mic the vanes?
Thanks
GM 6L80 Transmission Information Thread
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Any recommendations for where to get one or just take the chance of buying the new parts and just mic the vanes?
Thanks
WeekenderNutJob
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Is it worth changing the trans filter with an AWD and only 30K on the trans and no towing?
I have a 2008 Denali AWD. The previous owners put a crate trans in it about 30K miles ago. It is a people-mover and almost gets no towing. I am tempted to suck out the pan from the top, add fluid, and then do a fluid transfer flush from the cooler return line to get a full fluid flush from the converter. I feel like the chance of anything in the filter is low as it is a relatively new transmission and all the forums say that is a complete PITA or almost impossible to get the full pan down to change the filter. I have watched most of the YouTube videos on the topic and most say that the full dropping of the pan with the 6L80 and AWD and the Exhaust manifold are way more work than they are worth. Opinion on just a fluid flush vs the pan drop/filter replacement. Then in another 30k miles do the actual filter and fluid again?
I have a 2008 Denali AWD. The previous owners put a crate trans in it about 30K miles ago. It is a people-mover and almost gets no towing. I am tempted to suck out the pan from the top, add fluid, and then do a fluid transfer flush from the cooler return line to get a full fluid flush from the converter. I feel like the chance of anything in the filter is low as it is a relatively new transmission and all the forums say that is a complete PITA or almost impossible to get the full pan down to change the filter. I have watched most of the YouTube videos on the topic and most say that the full dropping of the pan with the 6L80 and AWD and the Exhaust manifold are way more work than they are worth. Opinion on just a fluid flush vs the pan drop/filter replacement. Then in another 30k miles do the actual filter and fluid again?
OP
OP
See if you can buy one from General Motors (either directly through the dealership or via GM Parts Direct / gmpartsdirect.com).
Check the condition of the fluid (appearance and smell) - if appearance is red and smells normal (i.e. not burnt or nasty), I wouldn't bother...Dex6 is designed to last at least 50k in normal DD/light towing applications - I'd check it again at 40k if it passes this initial inspection and no other issues are noted.
tom3
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OP
OP
Bumping this thread with a video on purchasing a used 6L80 or 6L90....While I generally don't recommend buying used automatics, many will take this approach due to budgetary and/or expediency reasons. So this video will give tips/pointers for how to weed out basket cases while giving important interchange information between different years/models/sub-models as well as explain the differences between three commonly used terms, 'fast adapt', 'reprogramming' and 'tuning' when discussing these transmissions.
Enjoy!
Enjoy!
WeekenderNutJob
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I will inspect as suggested but this post makes me want to just suck it out from the top, refill, and then maybe still pump it out of the trans cooler return and call it a day. Dont want to mess with the filter/gasket/exhaust bolts. Especially when I don't think the exhaust bolts would come off right now anyway, and I would just be making work for myself. Hand pump from Harbor freight, refill, and then the trans cooler line adapter on Amazon ( Hayden Transmission Line Adapter Fittings 397) seems like my best/quick and easy option.
Side note, I was shocked but getting the Dex 6 by the quart was cheaper than Amazon AC Delco by the gallon by almost 50%. Dont rule out your dealer for fluids I guess.
Side note, I was shocked but getting the Dex 6 by the quart was cheaper than Amazon AC Delco by the gallon by almost 50%. Dont rule out your dealer for fluids I guess.
ilikemikes
Member
Hey Nick, just got my Tahoe back from the Aus Tex guys. No more first gear bump but I noticed a tiny bump when its shifts to 2nd when cold. Only the 2nd day driving it but should I just give it a week or so to see if smooths out? Thx and thanks for the video bumps. I just hope I got a good rebuild.
OP
OP
Yes, give it about 10 complete drive cycles. Computer has to relearn your driving habits, etc and that takes some time...If it's still the same after 10 or so then call the trans builder back. Meanwhile check your fluid level when hot - make sure it's at the full mark on the dipstick...
ilikemikes
Member
Ok, will do. Thanks again for the guidance!
Hello,
Unfortunately my 6l80 gearbox needs repair, it jerks and the gears slip. I tried to find a competent mechanic who will rebuild it, but since cars with this gearbox are not offered in Europe, mechanics really appreciate the repair of this gearbox. I decided to repair it myself, I have the skills to do it properly. I would only ask for help in selecting the parts I need to use so that the gearbox works well for the next 3-4 years. I have a modest budget for this operation, but I hope that it will be possible to do it for 2500 dollars. In this amount I have to fit everything, i.e. the regeneration of the converter ~300 dollars, and the remaining parts along with shipping and taxes. I am considering buying the
circle D stage 2 kit https://www.circledtrans.com/6l80-level-2-performance-kit
or
RAYBESTOS stage 1 deluxe rebuild kit in pis https://www.ebay.pl/itm/17664493696...920dbd509:g:A8MAAOSwmPJmAmOn&itmprp=enc:AQAJA
You can advise whether any of these kits contain everything I might need for the rebuild? of course I am aware that I may have damaged elements that are not always subject to replacement. I also know that parts should be ordered after disassembly and inspection of the parts, but I cannot afford to block the car for so long.
I hope you will understand and try to help with choosing what to do.
Best regards
Unfortunately my 6l80 gearbox needs repair, it jerks and the gears slip. I tried to find a competent mechanic who will rebuild it, but since cars with this gearbox are not offered in Europe, mechanics really appreciate the repair of this gearbox. I decided to repair it myself, I have the skills to do it properly. I would only ask for help in selecting the parts I need to use so that the gearbox works well for the next 3-4 years. I have a modest budget for this operation, but I hope that it will be possible to do it for 2500 dollars. In this amount I have to fit everything, i.e. the regeneration of the converter ~300 dollars, and the remaining parts along with shipping and taxes. I am considering buying the
circle D stage 2 kit https://www.circledtrans.com/6l80-level-2-performance-kit
or
RAYBESTOS stage 1 deluxe rebuild kit in pis https://www.ebay.pl/itm/17664493696...920dbd509:g:A8MAAOSwmPJmAmOn&itmprp=enc:AQAJA
You can advise whether any of these kits contain everything I might need for the rebuild? of course I am aware that I may have damaged elements that are not always subject to replacement. I also know that parts should be ordered after disassembly and inspection of the parts, but I cannot afford to block the car for so long.
I hope you will understand and try to help with choosing what to do.
Best regards
OP
OP
$2500 US is doable if you don't have to replace your TEHCM.
I just ordered the Lvl2 kit from Circle D for a performance-oriented build that I'll be filming for Youtube in a couple weeks...I may or may not augment that kit with the Raybestos stage one friction set for the 4-5-6 as the Circle D kit comes with Borg Warner frictions (nothing wrong with those clutches) but the Stage Ones are a little more resilient to heat which is a big problem with that 4-5-6 clutch.
The CircleD kit comes with everything you'll need except for the electronics (TEHCM, IMS, Harness-speed sensors) and a few choice hard parts like the Sonnax billet 1-2-3-4 piston. I'd also purchase the Transgo clutch select valve and spring kit as well to augment what Circle D provides. If you're pushing over 500HP, I'd grab the Sonnax 4-5-6 billet hub/shaft assembly as well.
Hope that helps.
Thank you for your reply, I will decide on the circle D if the shipping costs are not too high.
I do not plan to increase the power in the car, I simply want a working gearbox. Can you tell me more precisely which TransGo kit you would buy?
Also, can you explain to me what the converter upgrade by installing a thicker clutch disc involves? I will ask a local contractor about such a service, but I do not fully understand what it is about.
I do not plan to increase the power in the car, I simply want a working gearbox. Can you tell me more precisely which TransGo kit you would buy?
Also, can you explain to me what the converter upgrade by installing a thicker clutch disc involves? I will ask a local contractor about such a service, but I do not fully understand what it is about.
OP
OP
Go to Transgo's website, click on 6L80 and you'll see all of the kits and parts offered for those transmissions...One of them is the clutch select valve kit...
Torque converter: Install a .070 thick Borg Warner HE converter clutch...You can also have the TC builder do a flanged hub for addl strength though it's not needed in a daily driver/stock application. Same with a billet converter cover - high performance only.
CTX-SLPR
Member
Nick,
How required are the pump mods in the Sonnax and Transgo kits?
I think I’m having problem related to the TECHM hydraulic side of things so pulling that part in the vehicle is a no brainer to replace the check balls, valves, and springs but the pump mods would require dropping and disassembling things which is a much bigger investment up front while trying to narrow it down.
Thanks
How required are the pump mods in the Sonnax and Transgo kits?
I think I’m having problem related to the TECHM hydraulic side of things so pulling that part in the vehicle is a no brainer to replace the check balls, valves, and springs but the pump mods would require dropping and disassembling things which is a much bigger investment up front while trying to narrow it down.
Thanks
OP
OP
I dont ever rebuild one of those transmissions without one of those two kits or an equivalent. Take that for what it's worth to you.
If you think the TEHCM is problematic either bench test it using a DVOM, 12-volt power supply and the Bosch 6L TEHCM test block. If you dont have the test block kit, you'll need to get it to a shop that has one.
Otherwise you're not going to be completely sure if everything passes the DVOM and 12-volt p/s tests...
CTX-SLPR
Member
Nick,
I think it's the hydraulic part that's the problem, i.e. valves or checkballs are sticking when it gets heat soaked as it's only evident after 45+ min of driving when you come to a stop or get moving from one. To me that seems like the first step is to pull the full unit and put the Sonnax ZIP kit in it minus the pump pressure regulator mods and see how things go. My concern is that without the pressure regulator mods the rest of the kit won't work properly and I'll just get more problems.
OP
OP
First thing I'd do if I were you is a line pressure test...Wear in the PR valve should show up there...Refer to the first page and post of this thread for the ATSG manual which has line pressure testing information...If you find that your line pressures are below normal, simply yank out and overhaul the unit completely.
I will be filming a 6L80 performance build up using one of Circle D's level 2 kits starting next week and will have the video series published to my YT channel towards the end of next week so you can follow along...It will be a complete and total overhaul with all parts and procedures shown.
CTX-SLPR
Member
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.
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.
Last edited:
ilikemikes
Member
Nick,
Took the Tahoe back to the shop. They said they did a software update and it fixed the 2nd gear clank. All good now. They also took it upon themselves to disabled the DOD while tuning, which I didn't ask for, but I'm ok with it. Thanks again for all the guidance.
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 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
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