2009-2014 6L80 better than 2015+?

[Prospect62]

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!

 

[Joseph Garcia]

I believe that the torque converter issues and failures have been with the 6 speed transmission since its debut.

There have been improvements to the 6 speed transmission itself over the years, as failure points were identified through driver use.

 

[Prospect62]

That's what I figured.

 

[mikez71]

'07-'14 might have less temperature issues than '15+, only because we lack the thermostat on the trans cooler lines.

Pretty sure 2012 has all the updates..

 

[j91z28d1]

what year did they switch to the 8 speed?

I know that one had a bad rep. 10 speed not. much better. it seems the days over tranny lasting 200k plus arw long gone. 5k sounds cheap thou, I thought new tranny was 8-10 installed these days?

 

[Prospect62]

5k sounds cheap thou, I thought new tranny was 8-10 installed these days?

It was around 5K and change for them to remove my bad 6L80 and replace it with a new one, and that was like two years ago. Not sure if a rebuild would have been more.

 

[Joseph Garcia]

Mine was around 5k as well.

 

[Prospect62]

From what I'm gathering, the 6L80 in the GMT900 trucks was pretty much identical to the 6L80 in the K2 trucks, minus the stupid thermostat (which is good I guess). Since I'm looking at a 2012 with AFM, I assume the factory tune does the same thing to the torque converter and I should expect no better from the 2012 Tahoe than I got from my 2016 Suburban.

I really like this truck but I really don't want to spend another $5000 when this one leaves me motionless.

 

[Joseph Garcia]

From what I'm gathering, the 6L80 in the GMT900 trucks was pretty much identical to the 6L80 in the K2 trucks, minus the stupid thermostat (which is good I guess). Since I'm looking at a 2012 with AFM, I assume the factory tune does the same thing to the torque converter and I should expect no better from the 2012 Tahoe than I got from my 2016 Suburban.

I really like this truck but I really don't want to spend another $5000 when this one leaves me motionless.

Those 2 transmission years are probably similar in build and improvements. BUT, the torque converter is separate from the transmission, and you have good choices there. If you replace the torque converter with a quality billet one, your new 6 speed transmission should have a good long life.

 

[Miami-Dade]

I replaced my transmission at 124K miles for 5K bucks back in 2021 in my 2016 Tahoe. It came with a 100K miles warranty from the G.M.C dealer.

I would not get a unknown 2012. You should just fix it and get it done at the Chevrolet/GMC dealer. Just IMHO.

 

[99Burbs]

Bought my 2013 with 90k 3 years ago. Changed trans fluid at about 110k or so. At 150k the trans grenaded itself. $4200 to rebuild with a billet TC. Hopefully it’ll last forever now.

 

[ReaperHWK]

I was quoted $5500 for a new tram y in my 2015 FYI.

 

[Marky Dissod]

From what I'm gathering, the 6L80 in the GMT900 trucks was pretty much identical to the 6L80 in the K2 trucks, minus the stupid thermostat (which is good I guess).
Since I'm looking at a 2012 with AFM, I assume the factory tune does the same thing to the torque converter,
and I should expect no better from the 2012 Tahoe than I got from my 2016 Suburban.
I really like this truck but I really don't want to spend another $5000 when this one leaves me motionless.

Have your tcm properly tuned, change the ATF every 30,000 miles, and you can put off that rebuild long enough to impress yourself.
The GM OE tune has a lot to do with how long the torque converter clutch lasts.

 

[Prospect62]

What's the most economical way to have the trans tuned in such a fashion?

 

[Marky Dissod]

What's the most economical way to have the trans tuned in such a fashion?

Can't answer this question responsibly. Cheaping out on the tune / tuner nearly always results in spending more money to rebuild transmission sooner,
which defeats the purpose of spending less money on the tune / tuner.
Same goes for 'canned tunes' / plug-in tunes.

Best way regardless of upfront cost is for the tuner to be sitting next to you, making adjustments to your tune based on realtime driving to suit your taste.
Next best is for tuner to make adjustments based on data files you exchange, based on the same realtime driving data, again, to suit your taste.
(Some simpler mail-order tuners are better than others, pcmperformance being among the best for over 20 years, but mostly for 4L60E & 6L80E stuff.)

 

[Prospect62]

I understand.

 

[B-train]

what year did they switch to the 8 speed?

I know that one had a bad rep. 10 speed not. much better. it seems the days over tranny lasting 200k plus arw long gone. 5k sounds cheap thou, I thought new tranny was 8-10 installed these days?

I believe the 8 speed was available in 2015 or 2016 in the Escalade and Denali. I love the 8 speed in my 2017. Combined with the 6.2, its just a fun combo to drive.

GM transmissions can last a long time if serviced properly. Keep the fluid clean with 40 to 50k intervals, ditch the thermostat on the 6 speed, and drive sensibly. Currently at 180k on the original 8 speed. My goal for the truck is 250k with original setup. At that time I'll decide what is the next step.

 

[Prospect62]

I believe the 8 speed was available in 2015 or 2016 in the Escalade and Denali. I love the 8 speed in my 2017. Combined with the 6.2, its just a fun combo to drive.

GM transmissions can last a long time if serviced properly. Keep the fluid clean with 40 to 50k intervals, ditch the thermostat on the 6 speed, and drive sensibly. Currently at 180k on the original 8 speed. My goal for the truck is 250k with original setup. At that time I'll decide what is the next step.

I'd be more inclined to agree if I didn't have to pay for a new one at 100K miles with a fluid change at 60K.

But I think for the number on the road vs. the number that have problems, you have to say that in most cases the odds are in your favor, especially if you maintain your stuff.

 

[Marky Dissod]

I'd be more inclined to agree if I didn't have to pay for a new one at 100K miles with a fluid change at 60K.

If you'd've changed the ATF @ 40,000 miles, transmission might've lasted longer.

 

[Prospect62]

Right....