Any issues with a 6.2 GM

LMLCHEVY · Aug 23, 2020

Trashy said:
I had a 2018 Gm 2500 with 6.0 and 4:11's
Now 2018 HC with 6.2 and 3:23's I added a Super Spring leaf and got better mileage then my 6.0 towing the same holiday trailer to the same camp spot.
I am curious about the 6.6 as well? and what gearing they offer?

They come with the 3.73 gears in the srw.
I had a 6.0 ccsb and it was awful to tow with compared to my dmax. Glad it was a company truck - hard on fuel. Only thing that sucks with the gm 1500 is the payload. Almost half that of the 1 ton depending on configuration.

LMLCHEVY · Aug 23, 2020

dgiles said:
20% more expensive for fuel, so 20% less comparable fuel economy. 28.2 becomes 23.0. Just need to compare if one cares. My duramax gets an easy 21 mpg at 125-130 and in BC diesel is 0.20 cheaper than regular. So, at 0.40 cheaper than premium, I am getting better comparable fuel economy than the 6.2 at nearly 30 mpg.

Right now diesel is cheaper. But where I live it was 30 cents more than reg before covid. And then traditionally in most of bc it’s always been more.

Switch · Sep 21, 2020

I have a 18 and the price for premium gas for the mileage it gets evens out, I get great fuel economy. The truck has all sorts of power and pulls my 26' TT with ease.

sethier · Oct 2, 2020

Was rolling down the highway and noticed a vibration when holding at a constant RPM. Felt like going over rumble strips every 50 feet. Stopped in at the dealership and they diagnosed as a torque converter clutch shudder. Apparently GM has started using a new transmission fluid to clear up this shudder as well as some shifting issues. So after a tranny flush and fluid change the shudder seems to have cleared up. This was done under a service bulletin and as such was covered under power train warranty. But a guy would have no idea this bulletin was out there until the issues arose. Seems to only be on the 8 speed transmissions. 2017 6.2 Sierra 8 speed 85000 km.

thump · Oct 3, 2020

You wouldnt happen to have have a copy of the service bullitin or a bullitin # to reference to? I have had my 2015 Denali with the 6.2 and 8 speed in the GM garage a couple times to have the tranny reflashed as it would shift eratic and have that same shuttering as you describe. The reflashing did nothing and they tell me there is nothing wrong, I disagree. I have 106000km on now and over my 5 year warranty as of August this year. Thanks

sethier said:
Was rolling down the highway and noticed a vibration when holding at a constant RPM. Felt like going over rumble strips every 50 feet. Stopped in at the dealership and they diagnosed as a torque converter clutch shudder. Apparently GM has started using a new transmission fluid to clear up this shudder as well as some shifting issues. So after a tranny flush and fluid change the shudder seems to have cleared up. This was done under a service bulletin and as such was covered under power train warranty. But a guy would have no idea this bulletin was out there until the issues arose. Seems to only be on the 8 speed transmissions. 2017 6.2 Sierra 8 speed 85000 km.

sethier · Oct 3, 2020

thump said:
You wouldnt happen to have have a copy of the service bullitin or a bullitin # to reference to? I have had my 2015 Denali with the 6.2 and 8 speed in the GM garage a couple times to have the tranny reflashed as it would shift eratic and have that same shuttering as you describe. The reflashing did nothing and they tell me there is nothing wrong, I disagree. I have 106000km on now and over my 5 year warranty as of August this year. Thanks

Also here’s a link to a bit of a write up on it

https://gmauthority.com/blog/2019/08/tsb-seems-to-fix-8-speed-automatic-gm-transmission-problems/

Trashy · Nov 18, 2020

Other than this......

I still have no issues with this truck and sure am going to miss it

plio7 · Nov 18, 2020

Sold mine with 297K and had no issues at all to mention.

Trashy · Jun 14, 2021

Still have the same ruck. Went from Calgary to Sylvan Lake yesterday. Averaged 122/kph and this was what I got

acesup800 · Jun 14, 2021

Trashy said:
Still have the same ruck. Went from Calgary to Sylvan Lake yesterday. Averaged 122/kph and this was what I got

View attachment 237759

Very nice, but remember those numbers are off by usually at least a full 1L/100 or more. At least on mine, they are off usually 2L/100km.

NoBrakes! · Jun 14, 2021

^^^ DUDE I'm happy when my wifes Santa Fe gets 8.1 on the highway at 120... thats awesome!!

doorfx · Jun 14, 2021

That’s pretty amazing as gm states 11.7 L/100k and I’ve never hit factory numbers.
You should keep that truck!!!

sethier · Jun 14, 2021

100 km into the wind and 100 km with the same tailwind. Cruise set at 110. Also have the Range module that deactivates the AFM so she don’t drop into 4 cylinder mode. No complaints here.

Trashy · Jun 14, 2021

doorfx said:
That’s pretty amazing as gm states 11.7 L/100k and I’ve never hit factory numbers.
You should keep that truck!!!

The 8 spd, 3;23 ratio, with 20's make it a highway cruiser. Between 120 and 135 is when I can hit those numbers

TylerG · Jun 14, 2021

Trashy said:
The 8 spd, 3;23 ratio, with 20's make it a highway cruiser. Between 120 and 135 is when I can hit those numbers

those are impressive numbers, my fiesta doesn't even do that good

Any issues with a 6.2 GM

LMLCHEVY

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Switch

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sethier

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thump

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