[RandyH]

My LM2 can get pretty good mileage with the 3.23 gears in it if I grandpa it a little, don't shift into 10th until above 62, but can hold it down to 60 if I don't ask for much throttle. I can get some pretty good mileage at 70-ish if I drive it like that all the time.

 

[Madbuzz41]

We've had our 2023 with the 3.23 gears for a month now but only ~150 miles. First 50 were all very short trips with almost no highway miles. And a lot of time was spent at idle trying to figure out the mission control computer system. Anyway, today I put ~100 mostly freeway miles on the rig. The average mpg reported by the computer went from 20 to 31 on the trip out. It dropped back to 29 on the way back because about 1/3 of the time I was in stop & go traffic on the freeway. On level road with virtually no wind, light rain and ~65 degrees the onboard numbers were showing low 30s for mpg. Up that to 70 and the mpg dropped about 4-5 mpg into the high 20s. The stop & go wasn't nearly the fuel burner it would be with gas. Overall the truck seems to do better than our 2009 Subaru Outback and under some conditions astonishingly better. Parking in an indoor garage... not so much!

Glad to hear you are enjoying your new 3.0 duramax! They are incredibly nice trucks that get insane mpg. I often wonder why anyone would drive anything smaller/less when I can drive this and get better mpg.

My LM2 can get pretty good mileage with the 3.23 gears in it if I grandpa it a little, don't shift into 10th until above 62, but can hold it down to 60 if I don't ask for much throttle. I can get some pretty good mileage at 70-ish if I drive it like that all the time.

View attachment 1121271

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That’s pretty good!

Just filled mine up, going to be doing some towing this weekend and wanted a full tank.
Going to be 37°C/99°F Saturday when I’m towing, super ideal temps! Hahah.

Here’s my last fill

Edit;
Sorry guys that’s 33.2mpg over 370.3 miles

Sent from my iPhone using Tapatalk

 

[redwngr]

My LM2 can get pretty good mileage with the 3.23 gears in it if I grandpa it a little, don't shift into 10th until above 62, but can hold it down to 60 if I don't ask for much throttle. I can get some pretty good mileage at 70-ish if I drive it like that all the time.

My LM2 was the same way with 10th.

I'm finding that the '23 with LZO will often drop into 10th a little sooner than the '21 with LM2.

I'm in a relatively flat area and have a bunch of locations I frequently travel to that I have choice of 'interstate' or rural 2 lane.

Taking out wind and traffic factors the mpg is always better at slower speeds.
(of course knowing this doesn't mean that driving slow is always desirable or practical)

 

[bhaydenhome]

The Banks iDash is a nice unit but a lot of money for an OBDII scan tool that you're going to tie to a single vehicle. It doesn't appear that they make the Banks Brake for the baby Duramax which is too bad. I know you are supposed to get engine braking in Tow Haul mode but I really can't tell that it makes any difference. That said, I've yet to try it when actually towing a trailer. I know the new 6.6L trucks have Tow Haul and an engine brake control. When we test drove the RAM I was much more impressed with how much it used the engine braking in just normal mode. I haven't tried the manual shift mode on the steering wheel. I would hope that this would tell you somewhere on the dash what gear you're in. And having only used Normal and Tow Haul don't know if there's a gear display in any of the others.

I did plug in my OTC brand OBDII scanner. It's last firmware update was 2017. I've never had reason to scan a vehicle newer. It recognized a lot of stuff but in data logging mode gear selection doesn't seem to be one of them; except time in neutral(s). Turns out 25% of the total 12 hours on the truck has been in neutral! That represents four hours of learning all the settings and controls.

 

[RandyH]

I just put mine into service mode to learn things and adjust results on my iDash, that way I don't have to run the engine to adjust things.

 

[bhaydenhome]

I just put mine into service mode to learn things and adjust results on my iDash, that way I don't have to run the engine to adjust things.

I'm still getting used to a vehicle that doesn't have a key. My scan tool refers to putting the "key" in the on position. I figured out this is the push engine start button without your foot on the brake. Back when we were test driving cars prior to buying our 2009 Subaru the only vehicle I remember that had a push to start instead of a key was Nissan. I can't say I'm a fan of it. For one thing my Silverado doesn't have a steering column lock because they can't get the chip. Mechanical interlock with a key seems like a really nice thing introduced in the 70's that has been lost. And if your battery dies, and it will, then what? Keep mine on a maintenance charger but still surprised the baby diesel isn't dual battery.

 

[Madbuzz41]

I'm still getting used to a vehicle that doesn't have a key. My scan tool refers to putting the "key" in the on position. I figured out this is the push engine start button without your foot on the brake. Back when we were test driving cars prior to buying our 2009 Subaru the only vehicle I remember that had a push to start instead of a key was Nissan. I can't say I'm a fan of it. For one thing my Silverado doesn't have a steering column lock because they can't get the chip. Mechanical interlock with a key seems like a really nice thing introduced in the 70's that has been lost. And if your battery dies, and it will, then what? Keep mine on a maintenance charger but still surprised the baby diesel isn't dual battery.

Steering column lock when you park it?
Mine does. When I park my truck I purposely turn left a hair before shutting off and after I do I shut it off and crank the steering wheel to the right and the column clicks and locks.


Sent from my iPhone using Tapatalk

 

[RandyH]

The fob has a key, the door has a lock, I’m not sure what having a dead battery will do? As far as keyless start, I don’t mind it, but I do remember old school and my 21 still has a column lock, my next one won’t, and that’s ok too.

 

[redwngr]

The trucks may or may not have a steering column lock -- seems to depend on build date.

This was in the 2022(refresh) order guide

This was in the 2023 Sierra 1500 order guide:

This is in the 2024 1500 sierra order guide

 

[redwngr]

Push button start pickups have 2 ways of enabling at least some accessory power without starting engine.

Accessory mode will time out. Doesn't activate as many items as Service Mode.
Service mode enables more items and doesn't have the 5 minute timeout feature.

Might be an iDash setting, but my iDash only turns on the screen when if the engine is running.
(There is a delay before it shuts off if Stop/start pauses the engine)



Accessory Mode (Amber Indicator Light) :
This mode allows some electrical accessories to be used when the engine is off.

With the vehicle off, pressing the ENGINE START/STOP button one time without the brake pedal applied will place the vehicle in accessory mode.

The vehicle will switch from accessory mode to off after five minutes to prevent battery rundown.


Service Mode
This power mode is available for service and diagnostics, and to verify the proper operation of the malfunction indicator lamp as may be required for emission inspection purposes.

With the vehicle off, and the brake pedal not applied, pressing and holding the ENGINE START/STOP button for more than five seconds will place the vehicle in Service Mode.

The instruments and audio systems will operate as they do when the vehicle is on, but the vehicle will not be able
to be driven.

The engine will not start in Service Mode.

Press the ENGINE START/STOP button again to turn the vehicle off.

 

[bhaydenhome]

@redwngr,
Thanks for the refresher course on Service Mode. My OBDII scanner wanted service mode but I only remembered Accessory Mode. IIRC the dealer had us put it in Service Mode to enable OnStar. The 2023 and it looks like the 2024 are steering column lock delete. The reason is that with push to start the lock is electronic rather than mechanical and they can't get enough of the required computer chip. There was a $50 credit on the invoice:

 

[bhaydenhome]

1st real road trip in our Silverado this weekend. Bellevue to Yakima via I-90 & I-82 (four major grades) we averaged 29.5 per the trip computer. With most of that at 70+ mph that's astounding. Coming home Yakima back to Enumclaw over Chinook Pass (410) we got a mind boggeling 32.5 mpg. This is a two lane mtn road and we were averaging ~50mph. This is a serious mtn pass and the truck responded like it was at sea level. I'm sure it would be different with a trailer but... still. We stopped in Enumclaw and from there to Auburn we were +34mpg but then hit stop and go traffic on I-5 in Seattle (I-405 closed for construction & a Seahawk game). Still the computer reported 29.2 for Enumclaw to Bellevue. No way our 2009 Subaru Outback would come close to these numbers and the truck was way more comfortable and easy to drive.

Side note. While in Yakima we got lost on a farm road and had our first experience with 4WD mode. It was Nice! Our 2000 Safari Van was AWD (no user adjustment required or possible) was awesome; but being in AWD ALL the time sort of sucks. Being able to push a button and not have to get out and lock the hubs like my old 72 Bronco was deluxe. Haven't figured out if you have to be stopped to shift or not (old Jeeps could do it on the fly). TOO MANY DAMN BUTTONS! Anyway, truck got us idiots out of a jam.

 

[badger27]

Haven't figured out if you have to be stopped to shift or not (old Jeeps could do it on the fly).

You only have to be stopped to shift into 4 LO.

 

[redwngr]

Similar for shifting out of 4L

 

[bhaydenhome]

Thanks all. We sort of figured out that you had to be stopped to shift to 4WH. I'm almost wishing it was as easy as getting out and a turning a hub like my old Bronco. Anyway, truck did it's job and got us out of a bind. Souldn't need a computer science degree to drive a truck. And...it appears the computer isn't as smart as it thinks it is as the lock on remote setting has gone completely rouge.

 

[badger27]

We sort of figured out that you had to be stopped to shift to 4WH.

You don't have to be stopped to shift to/from 4wd HI and 2wd. I've done that at 35mph.

 

[Hate2looz]

As badger said, no need to stop when shifting from 2WD to 4WD High, just push the buttons. If going into 4 low then you need to stop the truck (imagine accidentally pressing 4 low when traveling 50 MPH…! 😳, that’s why they do it that way). It doesn’t get much easier than that. I’ve done the shifting from 60mph in the winter when passing someone and it’s snowing out. Works seamless.

 

[redwngr]

As badger said, no need to stop when shifting from 2WD to 4WD High, just push the buttons. If going into 4 low then you need to stop the truck (imagine accidentally pressing 4 low when traveling 50 MPH…! 😳, that’s why they do it that way). It doesn’t get much easier than that. I’ve done the shifting from 60mph in the winter when passing someone and it’s snowing out. Works seamless.

Of course the button sends a 'shift request' to the computer, which then decides if it's ok to even try the shift...before sending out the shift command.


Shifting Into 4L

1. The ignition must be on and the vehicle must be stopped or moving less than 5 km/h (3 mph) with the transmission in N (Neutral). It is best for the vehicle to be moving 1.6 to 3.2 km/h (1 to 2 mph).

2. Press 4L.
The actual 4x4 shift request is only made after the button is released.
The 4x4 graphic will remain flashing until the shift request has completed.
A DIC message displays to indicate that the 4x4 transfer case has been requested to shift to the new desired state.
Once the 4x4 shift has completed, the DIC message disappears, the 4x4 graphic stops flashing and the current setting is indicated.

If vehicle speed is higher when shift request occurs, a DIC message displays. Reduce vehicle speed.
If the transmission is not in N (Neutral) when shift request occurs, a DIC message displays. The vehicle will allow 20 seconds for the shift to occur. After this time, a graphic in the instrument cluster will indicate that the transfer case is in 4L.

Caution
Shifting the transmission into gear before the requested mode indicator light has stopped flashing could damage the transfer case.

If the transmission is not shifted into N (Neutral) or the vehicle has not slowed to 5 km/h (3 mph) within 20 seconds, the transfer case will remain in its original state.
This will be indicated in the instrument cluster.

With the vehicle moving less than 5 km/h (3 mph) and the transmission in N (Neutral), attempt the shift again.