Agriont

30-40% is significant... especially if towing. I'm not so concerned when I'm not towing because the 6.2 is quite frugal under my foot empty. I'm looking at distance between fill ups. I'd like to know real world towing expectations from the 3L per tank towing 5k lbs.

Just telling you my experience. Rural, small town gas stations don't have 91 on pump in my area.

I jumped from a 2010 5.3 to 6.2. The 6.2 is more fuel efficient. The only concern I have with it is the availability of premium fuel on some of my recreation routes. Mostly 87 octane, regular unleaded is all available at gas stations. I'm wondering if something like Lucas octane boost would be me 4 points with a 15oz bottle per 25 gallon fill up. It is that or carry a lot of gas cans. I had a bigger capacity tank in my older GM as well, which I prefer.

That is pretty good. How heavy is your trailer and what amount of weight do you carry in it and the truck when you tow? What is the milage on hills? Mine with 5,500lbs of trailer (tandem 14' with 4' V, 86h x 7.5w) and kit is about runs about 16 - lower when towing... down to 7 MPG on hills at times. I can see the needle drop as it drinks gas.

I'm was surprised by it too, coming from a 5.3L SLT Z71. The 6.2l shifts between four and eight cylinders, I don't even notice when it does.

No. Stock. 350 mile run highway. It cruises at low rpm. I said I've gotten 23-24 highway.

70-75 mph, highway average. It does well around town too.

I've experienced 23-25 MPG not towing. I really dislike the gas tank size in my Denali. It is a limiter for my purpose, especially when fuel use drops to 8 MPG on hills. I need more range, more capacity without the need to jerrycan gas. It is a pita. I have the magneride suspension. I use to have a Z71, and miss it for payload and towing. I wish GM had the option of Z71 on a half ton Denali. I'd also like a full size bed, 8ft but don't see that happening.

Not worth the trade for certain but I am curious to how the 3.0l tows and to real life fuel economy. I think my truck has the same towing rating. The 6.2l is not a slouch and yes, it is fast. Fuel economy is exceptional when not towing.

My issue with my current truck is the gas tank size, the 6.2 does well for the most part but when doing 6k clicks on one trip over a two week period, stopping to fill up is a pita when there aren't many gas stations where I travel for recreation. It means I have to carry a lot of gas cans. My truck has the Magneride shocks.

I have a 2017 with the 6.2. I do tow a tandem 19' enclosed trailer with it, not every day but enough to feel the sting of the reduced fuel economy. I'd like to know what anyone with the 3.0 are experiencing when towing in terms of handling and fuel economy.

I'm not a mechanic but obviously the truck has problems and the valve body showed in code apparently. I've heard from other truck owners who've had it done in their vehicles. I've read that the valve body cover design is an issue, thus the replacement. A friend of mine has a 2019 GM 5.3 w/8sp. His truck is as bad as mine, but also has much more milage. His dealership told him there was nothing wrong. I suggested he go to another dealer.

Valve body as well.

My dealer is well aware of the problem with the 8sp. I too hope it resolves the problem and not damage has been done elsewhere. I have low milage on my truck and I hope this TC replacement last well beyond 40k miles. I'm leery of it at the moment and hate the idea of having all of the guts of the vehicle being torn apart and then put back together.

2017, 6.2 8sp.. replacing the TC this week. Tried the first steps, several attempts to relearn but tech said the shifts are still way out of place. I hope it does the trick.. if not, I'm done with it.

Had the transmission flush and fluid changed. Still not as liquid smooth as it was new but haven't had the kick so often between 1-2 and back. If it gets worse, I'll bring it back.

I guess I'm asking for experience from those who have made the change in terms of the vehicle they drive, specifically the 6.2 and the 8 spd. I haven't decided on a change at this point. I also, don't want to void any warranty or give GM a chance to say I didn't follow their service specifications/oil etc.

I used AMSOIL in an older vehicle because I read it was good stuff. I didn't keep the vehicle long after that so haven't the experience of seeing the benefit, which I do not doubt. I too am all in on the best oils and cold starts, heat etc. I tow a little, (3200lbs) or so, most of it during the dead of winter. I believe that maintenance is the key not only to longevity but also to performance. My question ref the transmission was specific to the shifting issues with the 8spd. If I can mitigate the problem by switching out the Mobil to AMSOIL, I will do it and the engine oil and filters too. I love this truck of mine and the 6.2 is smile maker.

I have the same truck. Recent bulletin for 8spd transmission called for a flush and Mobil 1 Synthetic LV ATF HP fluid if you've experience rough shifts. Have you changed yours with this juice or have you used AMSOIL for the transmission as well as the engine oil?

Same but definitely notice the shift in first and second when cold. It wasn't like this when new.

Had the same thing done a couple of weeks ago. Seems a little better. Shifting is nowhere near as quiet as when it was new. Keep going back until something is found to remedy it, I plan to.

Happened twice today... 2nd to 1st... parking lot.

I'll keep it in mind.

I have a 2017 Sierra Denali 6.2 4wd. I've only heard a clunk when coming to a stop at low speed just after a cold start. Doesn't happen every time, but very noticeable when it does. I've read some folks refer to something similar with their trucks. I've got about 20k miles on it.

I'm thinking about a tuner as well. Wonder if it is worth it and whether there is significant change. Would not send anything away to be messed with. I'd like to cut out the speed limiter, would like to tune for better towing when needed... if possible. Something easy to use, multiple programs.