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6 Speed Transmission Hack Now an official GM procedure

rav3
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Spurshot Senior Enthusiast

Spurshot

Posted
Posted (edited)

Lots of good info in this thread. 

 

I'm resurecting this old thread, since I'm about to drop the pan on my 2014 6L80 at the 94k mark.  I figure I'd put a new pan on with a drain plug and do this pill flip at the same time.  ...if I haven't already killed this trans.  I have a new GM pan and I'll weld in a bung today and get to it.   I'll check for how much metal is in the pan.  Dreading this...

Edited by Spurshot
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rav3
rav3

This may be old news to some, but I ran across this Service Bulletin "#21-NA-299 - Information on Installation of a New Thermal Bypass Valve (TBV)" where GM now does the "Hack" with a new up-dated kit

Grumpy Bear
Grumpy Bear

That's cooler than I would have thought. Think I saw 104 F as a 'trigger' in a tuning table 1SLOW1500 showed once.    Unlike the motor 'moisture' is not generated in a transmission as a comb

jwhjr
jwhjr

My parts showed up today and I plan to swap them out this weekend hopefully.

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Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted
13 minutes ago, Spurshot said:

Lots of good info in this thread. 

 

I'm resurecting this old thread, since I'm about to drop the pan on my 2014 6L80 at the 94k mark.  I figure I'd put a new pan on with a drain plug and do this pill flip at the same time.  ...if I haven't already killed this trans.  I have a new GM pan and I'll weld in a bung today and get to it.   I'll check for how much metal is in the pan.  Dreading this...

 

If it looks healthy a consideration may be to buy and install a billet converter such as Florida Converters Billet unit. Unless this truck of yours is the V6 in which case they use a different style and very reliable converter clutch. 

Spurshot Senior Enthusiast

Spurshot

Posted
Posted
7 hours ago, Grumpy Bear said:

 

If it looks healthy a consideration may be to buy and install a billet converter such as Florida Converters Billet unit. Unless this truck of yours is the V6 in which case they use a different style and very reliable converter clutch. 

Marty, I have a 5.3L.  Not sure if these are problematic or not.

Spurshot Senior Enthusiast

Spurshot

Posted
Posted

I shaped the threaded bung I made last week got it welded on today.  I can TIG weld a bit, but my friend has a full-time welder that is good, so I don't bother anymore.  20220613_144647.thumb.jpg.ec311f887bb2a6941de2962b0f490a9f.jpg

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Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted (edited)
8 hours ago, Spurshot said:

Marty, I have a 5.3L.  Not sure if these are problematic or not.

 

You decide 😉 

 

https://www.sonnax.com/tech_resources/845-6l80-6l90-transmission-tech-advisory-consider-an-updated-converter-in-your-next-rebuild

 

Above is worth the read. 

 

****************************

 

77-JMBXSD is the billet unit (77JMBX is the standard part, Take note of the note in that column)

 

https://www.floridatorqueconverters.com/transmissions-chevrolet-6L80E-6L90E.html

 

Enjoy 

Edited by Grumpy Bear
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Spurshot Senior Enthusiast

Spurshot

Posted
Posted (edited)

I did the pill flip during the fluid change.  Installed the pan with the drain plug, new filter, purged about 4 qts after the change to get clean fluid flow. Old fluid wasn't burnt.  Total replaced fluid was about 13.5 qts of AC Delco Dex VI. 

 

The debris in the pan didn't look bad.  

20220616_133756.thumb.jpg.b749d77f754e0edde827c281656e1c36.jpg

Edited by Spurshot
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Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted
1 hour ago, Spurshot said:

I did the pill flip during the fluid change.  Installed the pan with the drain plug, new filter, purged about 4 qts after the change to get clean fluid flow. Old fluid wasn't burnt.  Total replaced fluid was about 13.5 qts of AC Delco Dex VI. 

 

The debris in the pan didn't look bad.  

 

 

Nice job and what a great result. Well done sir. 

Spurshot Senior Enthusiast

Spurshot

Posted
Posted (edited)
19 minutes ago, Grumpy Bear said:

 

Nice job and what a great result. Well done sir. 

 

Thanks, but you didn't see the mess I made.  Had to go to the DIY car wash to clean up the bottom of the truck and I showered with Dawn dish detergent. 🥴

 

Still thinking about how to go about that converter changeout.   I know an acquaintance (good friend of my brother) that owns a Jeep/truck 4x4 shop that would be game for the job. He's one of the few places I trust to work on anything.  He rebuilt a transfer case on a 1999 1/2 2500 I had.  But he's about 60 miles away.  I could flat tow my jeep out to drop it off.  

 

The other nagging voice in the back of my head is the DOD delete.  I put 33x12.50 tires on it when it was almost new and I noted that with the extra load from the tires DOD didn't engage on flat ground, only when I was going downhill.  So, it doesn't get much use and may have saved it so far.  

Edited by Spurshot
Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted
27 minutes ago, Spurshot said:

The other nagging voice in the back of my head is the DOD delete.  I put 33x12.50 tires on it when it was almost new and I noted that with the extra load from the tires DOD didn't engage on flat ground, only when I was going downhill.  So, it doesn't get much use and may have saved it so far.  

 

Correct. DOD is load/demand based as your observations confirm. If you are as diligent about your oil as your are about the rest of your truck that DOD will not be an issue. It's kind of proved that already, right? 😉 

 

If it were going to fail due to a design flaw, material issue or quality control problem it would have done so by now. The job moving forward is keeping the moving parts clean and preventing aeration of the oil. You are doing fine sir. 

 

LOL I've take then Dawn bath.....SLICK....

Spendit Enthusiast

Spendit

Posted
Posted

Spurshot - Curious if the pan drop was as bad as some report - wedging up engine, small hands to twist it out between cross member and all the wood chunks and straps to have on hand? I have the 5.3 CC with 100K now

  • Like 1
pokismoki Senior Enthusiast

pokismoki

Posted
Posted (edited)
On 6/14/2022 at 3:00 AM, Grumpy Bear said:

 

You decide 😉 

 

https://www.sonnax.com/tech_resources/845-6l80-6l90-transmission-tech-advisory-consider-an-updated-converter-in-your-next-rebuild

 

Above is worth the read. 

 

****************************

 

 

I wouldn't go so far as to say its the converters fault as the guys at sonnax say.  it's more of GM's strategy to immediatly activate the TCC in all gears especially 1st, 2nd-3rd. those gears have the most torque  and inflict a lot of wear on a flimsy tcc clutch.  if you looked at older GM strategy in the 4 speeds they never activated TCC in 1-2nd gear, they saved the lock up for overdrive gears to minimize wear and tear and gain MPG.

 

if you do get a new converter order the 6 BOlt 6L90 unit and retune the tcc 

Edited by pokismoki
pokismoki Senior Enthusiast

pokismoki

Posted
Posted
On 6/21/2022 at 9:05 AM, Spendit said:

Spurshot - Curious if the pan drop was as bad as some report - wedging up engine, small hands to twist it out between cross member and all the wood chunks and straps to have on hand? I have the 5.3 CC with 100K now

its easier to remove the crossmember mounting bolt under the rear of trans, and just lift the unit with a small jack

  • Like 1
Black02Silverado Senior Enthusiast

Black02Silverado

Posted
Posted
2 hours ago, pokismoki said:

its easier to remove the crossmember mounting bolt under the rear of trans, and just lift the unit with a small jack

My 2016 Suburban was a major pain and no matter how much I did the jacking and exhaust pull down as most stated I couldn't get the pan out.  Had to loosen the exhaust at the manifolds to allow enough room to get it off. I guess it all depends on the vehicle.  Some can get it some can't.

Capt Bob Enthusiast

Capt Bob

Posted
Posted

I used this hack and it worked very well on my truck. As Nick noted above, YMMV.

 

16LT4 Enthusiast

16LT4

Posted
Posted

If I can avoid touching exhaust connections, I will at all costs.  Getting it back together to find an exhaust tick due to disturbed connection is annoying, to say the least.

 

My method, which may be similar to the video above that I didn't watch, is to anchor a ratchet strap to the ground and gently pull the exhaust cross-over down while also lifting up at the transfer case a little bit.  This provided enough wiggle room to maneuver the pan out, but it was still a game of tetris.  It was still annoying, but I was able to get the pan out without [much] spillage, the trick is to keep a bolt loosely in one end of the pan to act as a hinge, will letting fluid pour out the other side into a large catch basin; loosening that bolt allows the pan to rotate more, allowing more fluid loss.

 

Not wanting to deal with that process anytime soon, with the pan out at 73k miles, I drilled a hole in the pan at a good location, made my own castle nut with a cut-off wheel, welded it to the inside of the pan, and installed a standard 14mm hex GM drain bolt (with gasket) from Autozone.  Now, 25k mile drain-fills are easier than oil changes.  On my last drain/fill (at around 90k IIRC; I'm currently at 102k miles) I used Redline D6, and a bottle of Lubegard Red.  I use the LGR on every transmission I own/service, and it does make a difference.  Before even doing anything with the AT thermostat, I saw an immediate drop in ATF temp by a few degrees after the LGR was added.

 

 

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