GM 6L80 Transmission Information Thread

CTX-SLPR · Oct 7, 2024

CTX-SLPR said:
Nick,

Is there a place you can buy a preassembled pump and bellhousing? Local guys seem to have gotten out of the game of doing job work so looking for a contingency plan if the pump is damaged when I pull the trans apart for testing and a Zip Kit. I can find new ones in knock down kit form but without the test tool to see if the vanes are too tall a preassembled one seems like a better bet.

Thanks

Nick,

Any recommendations for where to get one or just take the chance of buying the new parts and just mic the vanes?

Thanks

WeekenderNutJob · Oct 16, 2024

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?

NickTransmissions · Oct 16, 2024

CTX-SLPR said:
Nick,

Any recommendations for where to get one or just take the chance of buying the new parts and just mic the vanes?

Thanks

See if you can buy one from General Motors (either directly through the dealership or via GM Parts Direct / gmpartsdirect.com).

WeekenderNutJob said:
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?

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 · Oct 16, 2024

WeekenderNutJob said:
Is it worth changing the trans filter with an AWD and only 30K on the trans and no towing?

I did ours at 30K, dropped the pan, new filter, gasket, and refilled. I wanted to see what was in the bottom of the pan and I wanted to take off the nuts on the manifold to pipes flanges and hit them with neverseize for the future. Not really a lot of work at this point, could have been a real bear a couple years down the road. My pan was clean and shiny, pretty relieved at that.

NickTransmissions · Oct 16, 2024

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!

WeekenderNutJob · Oct 16, 2024

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.

ilikemikes · Oct 16, 2024

NickTransmissions said:
It's up to you on the billet converter cover; I typically only do them on HP or HD builds but sometimes the customer wants one, regardless.

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.

NickTransmissions · Oct 16, 2024

ilikemikes said:
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.

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 · Oct 17, 2024

NickTransmissions said:
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...

Ok, will do. Thanks again for the guidance!

Smolski · Oct 30, 2024

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

GM 6L80 Transmission Information Thread

CTX-SLPR

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WeekenderNutJob

TYF Newbie

NickTransmissions

Sin City

tom3

Full Access Member

NickTransmissions

Sin City

WeekenderNutJob

TYF Newbie

ilikemikes

TYF Newbie

NickTransmissions

Sin City

ilikemikes

TYF Newbie

Smolski

TYF Newbie

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