2009-2014 6L80 better than 2015+?

[alvocado]

I changed trans fluid every 50K and my torque converter went at 211k miles.

 

[swathdiver]

The transmission in my 2016 Suburban made it to around 100,000 miles before it gave up and cost me $5000.

I'm looking at a 2012 Tahoe and was wondering if the older 6L80's were free of this horrible torque converter and high temperature issues that the K2 trucks have?

I don't know much about the 2007-2014 generation trucks. Thanks guys!

The 6L80s last longer in the GMT900s because of the different cooling system. They generally fail at about 160K miles if they've never been serviced and the first failure point are the solenoids in the TECHM. The torque converter clutch lining issue seems related to heat and the higher horsepower 6.2s in the GMT-900s.

Run them on the severe service schedule, changing the fluid every 40K miles or so and they ought to last a long time. It is not uncommon for them to exceed 200K miles or even 300K miles. A few years ago, a work truck with a 6L90 drove into the shop (Precision Transmission) for overhaul with over 312K miles on it.

One of mine has over 220K on it and still runs just fine.

 

[Prospect62]

The 6L80s last longer in the GMT900s because of the different cooling system. They generally fail at about 160K miles if they've never been serviced and the first failure point are the solenoids in the TECHM. The torque converter clutch lining issue seems related to heat and the higher horsepower 6.2s in the GMT-900s.

Run them on the severe service schedule, changing the fluid every 40K miles or so and they ought to last a long time. It is not uncommon for them to exceed 200K miles or even 300K miles. A few years ago, a work truck with a 6L90 drove into the shop (Precision Transmission) for overhaul with over 312K miles on it.

One of mine has over 220K on it and still runs just fine.

Thank you for that reply, it's informative and encouraging.

I just bought a 2012 with 111,000 and based on the Carfax, no transmission service history. It may have been done, it may not.

Based on your experience, would you recommend a pan drop and filter change, a flush, or leave it alone and hope to get to 160,000?

 

[swathdiver]

Thank you for that reply, it's informative and encouraging.

I just bought a 2012 with 111,000 and based on the Carfax, no transmission service history. It may have been done, it may not.

Based on your experience, would you recommend a pan drop and filter change, a flush, or leave it alone and hope to get to 160,000?

Change it.

When I bought mine in 2017 it had about 113K on it. I took it to the dealer and they did a fluid exchange on it at about 117K. Next fluid exchange was done at home at around 153K and then at about 184K we finally dropped the pan for the first time. It wasn't that bad at all. So while the shop manual calls for dropping the pan and changing the filter, the dealerships don't do that anymore, they just do the fluid exchanges. Truck just is in the 221K range now and we did another fluid exchange at home again a few days ago. The fluid was quite dark but smells normal. Took a sample to send off for analysis, this transmission's 2nd or 3rd so far.

One of my 6.2 pickups is also due for the transmission fluid to be changed. She's in the 130s now and we did it at around 90K or so. All fluid exchanges so far.

The third truck, our 2012 6.2 Sierra had its transmission go out in the 130s (TECHM). She has had a 6.5" lift and running 35s since almost new. One daughter drives the truck and refused to change the fluid. A refurbished transmission and new torque converter were installed and she also refused to change the fluid in that one. The fluid was really dark like mine last time we checked. Now that she's married, her husband will change it soon.

Here's a photo of the inside of my filter at 184K:

 

[Prospect62]

Perfect, thanks. I'll wait until the weather warms up here in CNY and do a pan drop and filter change, probably in May. I'll only put 4000 miles on it between now and then and I'm pretty gingerly. I always try to drive in a style that makes the transmission hunt less and go in and out of OD less.

I've been blown away watching the trans temps in this rig compared to my old 2016 Suburban. This one hasn't really gotten above 160 no matter what. The Suburban would push 195 pretty much all the time. It's gotta be a factor in the 6L80 failures and as you confirm, it appears to be.

 

[Charlie207]

Perfect, thanks. I'll wait until the weather warms up here in CNY and do a pan drop and filter change, probably in May. I'll only put 4000 miles on it between now and then and I'm pretty gingerly. I always try to drive in a style that makes the transmission hunt less and go in and out of OD less.

I've been blown away watching the trans temps in this rig compared to my old 2016 Suburban. This one hasn't really gotten above 160 no matter what. The Suburban would push 195 pretty much all the time. It's gotta be a factor in the 6L80 failures and as you confirm, it appears to be.

I almost always put the transmission in manual mode and leave it in Gear 5 around town, or in any state road that is under 65mph, to help minimize the hunting & pecking for 6th gear.

I also bought one of those fluid extractors with 10ft of hose attachments to exchange ATF much easier between filter changes.

Swapping the TQ at 180k was a good idea, and I'm getting closer to 200k on my 6L80. I've had a BBP tune in it since about 155k when I got the rig.

 

[Prospect62]

I almost always put the transmission in manual mode and leave it in Gear 5 around town, or in any state road that is under 65mph, to help minimize the hunting & pecking for 6th gear.

I also bought one of those fluid extractors with 10ft of hose attachments to exchange ATF much easier between filter changes.

Swapping the TQ at 180k was a good idea, and I'm getting closer to 200k on my 6L80. I've had a BBP tune in it since about 155k when I got the rig.

If it weren't for the aggressive downshifting when slowing, I'd keep it in tow/haul at all times. I just like the way the truck feels and performs and I think it does, too.

I should probably get a good tune.

 

[Charlie207]

If it weren't for the aggressive downshifting when slowing, I'd keep it in tow/haul at all times. I just like the way the truck feels and performs and I think it does, too.

I should probably get a good tune.

Just get the BBP ECM/TCM tune. It's the best bang-for-your-buck preventative maintenance protocol you can do for your drivetrain, disguised as a performance upgrade.

Edit: and change the TC for a billet-backed unit. The CVC unit from Summit is probably similar pricing to the factory JMBX unit. The LUK converter that seems to be fairly new for our rigs is neat, but I've seen a few threads around here with some tuning questions/issues. I think in a stock role it works perfectly fine, but I could be off-base on that.

 

[swathdiver]

I almost always put the transmission in manual mode and leave it in Gear 5 around town, or in any state road that is under 65mph, to help minimize the hunting & pecking for 6th gear.

3.08 gears?

 

[Charlie207]

3.08 gears?

3.42 - there's lots of hills and valleys around here. Almost nothing is flat/level unless you're driving along a river, and even then it's never really level for long.

 

[Prospect62]

3.08 gears?

*Edit sorry thought that was for me

 

[Prospect62]

Just get the BBP ECM/TCM tune. It's the best bang-for-your-buck preventative maintenance protocol you can do for your drivetrain, disguised as a performance upgrade.

Edit: and change the TC for a billet-backed unit. The CVC unit from Summit is probably similar pricing to the factory JMBX unit. The LUK converter that seems to be fairly new for our rigs is neat, but I've seen a few threads around here with some tuning questions/issues. I think in a stock role it works perfectly fine, but I could be off-base on that.

I'll look into that tune. I'm trying not to dislodge the tranny from the truck so confidence is low that I'll be upgrading the TC before the tranny goes.

 

[Charlie207]

I'll look into that tune. I'm trying not to dislodge the tranny from the truck so confidence is low that I'll be upgrading the TC before the tranny goes.

I hear you on that. I was swapping engines, so figured is was a "now or never" decision.

 

[Prospect62]

WOW 400 beans for a Black Bear tune. Ouch.

 

[Charlie207]

WOW 400 beans for a Black Bear tune. Ouch.

No, you want this one.

EFILive AutoCal V3 Custom GM Tuning - Black Bear Performance

Unlock your vehicle's potential with an EFILive AutoCal V3 and BBP's custom GM tuning. Gain horsepower, torque, and responsive tuning. Easily returns to stock.

www.blackbearperformance.com

 

[Prospect62]

Even better.

 

[Charlie207]

Even better.

$2 a day for a year. You can search the forum, and see that no one really has anything but good things to say about the tune. It really improves the entire driving experience.

 

[West 1]

In California you can't modify the engine tune, it will be caught at the 2 year smog inspection. With the 08 6.2L I am very happy with the factory engine tune, it runs like a beast.

I would like a Tranny tune which is not regulated. Last time I checked Black Bear wanted almost $600 for the tranny tune by itself?

My 6L80 is approaching 147,000 miles, had a new TECHM installed at 80,000. I currently have a small rear main seal leak that I plan to fix soon. I will buy a new Torque converter and install it while I have the tranny removed for the rear main seal work.
I hope that will keep it reliable for a while longer.

Edit: Feb 2026 pulled the tranny for a new rear main seal on the engine, installed a brand new Luk Torque converter. $400 delivered to my house. Nice unit, drives just like the stock converter but the lock up is stronger. Stays locked up longer on mild accelerations. I like it so far.

 

[swathdiver]

WOW 400 beans for a Black Bear tune. Ouch.

Worth every penny and then some. The tune is the foundation upon which all other mods build upon. It's also your best bang for the buck performance mods wise.

 

[swathdiver]

In California you can't modify the engine tune, it will be caught at the 2 year smog inspection. With the 08 6.2L I am very happy with the factory engine tune, it runs like a beast.

CARB has been stripped of just about all authority now. They're laying off workers in droves. They'll keep up with or do safety inspections to keep the money machine going.