2023 5.3L Assessment

[Jimbeau]

They’ve been out long enough now.. I’ve talked with coworkers who’ve pumped up some decent mileage without issues. How’s yours holding up? Recommendations for maintenance, avoiding lifter issues, etc?

 

Purchased mine new in Jul 2023. It was fresh off the car hauler, not one that had been sitting during Covid. Mexico build. I’ve had zero issues. Haven’t been back to the dealership once since.
I was super deliberate during the 500 mi break in period. Varied the rpm per the manual. Well, book says “speed” but I mainly focused on smoothly varying RPMs for increasing intervals. This involved a LOT of backroad driving in manual mode. Ultimately ran some fairly high RPMs. Changed oil at 3K (probably should’ve changed it at 500mi) after the break in period. Changed it again at 7K.
I only have 8,200 miles currently but couldn’t be happier. 

-Oil: Valvoline Extended Protection 0W20.

-Undercarriage: Day 1.  Applied Zip Cor-Ban 35 or Zip D-5067NS to all exposed metal, hardware, etc. 

-Fuel treatment: AC Delco 10-3012 prior to 2nd oil change. I intentionally add this 1-2 fuel tanks prior to the oil change. Will do it every 3rd oil change going forward. 
-Fuel type: Only use Top Teir gas. Cosco is my choice. Cheap and certified on the TT list. 
 
 

[PunchT37]

2025 5.3 with 8200 miles. Changed my oil at 500 miles also. Switched to 5w30 at that time. 2 oil changes since. I run the piss out of mine. Runs like a clock. Not one drop of oil added. Stays on full. 

[TrueBlue]

'23 LT 5.3L with 9200 miles on it now. Bought it 8/23 with 35 miles on the clock. Driven in L9 since new. No issues outside of the aero vents not cycling a couple of times in freezing weather. Love the truck. I have a Range DFM disabler for it but am still making sure I won't have any warranty issues that would require me to pull it, before I install it. Already in the habit of pushing the disable button on the dash for the auto start stop defeat, and shifting into L9 before moving. I put a Magnaflow 14" dual out muffler on it early and love the sound. I do change my oil every 3K. 

[Jimbeau]

Interesting, I haven’t considered driving in L9. Is that better for the transportation somehow? It does run a super low RPM, especially in slow traffic.  
Yeah, that auto start/stop is a ******! Wish there was someway to disable that crap!!!!!
I worry about the DFM issues as well. My understanding is that disabling it makes it run on all 8 alright but doesn’t exactly solve the problem. The DFM hard parts (that tend to fail) are still installed. 

[TrueBlue]

Running in L9 prevents DFM from activating. The jury is out on whether or not it could/would prevent lifter failure though I'm using it to hedge my bets. If the spring mechanism on them that provides the lifter the ability to "deactivate" is not used, well theoretically that part of the system won't fail. From what I've read and heard most of the recent (2019-2021) failures were due to bad batches of lifters which were out of spec in their heat treatment hardness. That was reportedly fixed before our trucks were produced. And I haven't heard of any failures in our year's units. Doesn't mean we won't but by keeping our oil changed and clean, and for me driving in L9 is my (and others) way of hopefully avoiding that type of failure.

Driving in L9 doesn't make a significant difference in fuel economy, and the transmission does still automatically start off in L1 and progress up, so it's behavior is no different. It's just that the system sees L9 as a signal that tells it DFM is not wanted/needed and so it doesn't engage.

Edited November 20, 2025 by TrueBlue

[Bikerjon]

2 hours ago, TrueBlue said:

Running in L9 prevents DFM from activating. The jury is out on whether or not it could/would prevent lifter failure though I'm using it to hedge my bets. If the spring mechanism on them that provides the lifter the ability to "deactivate" is not used, well theoretically that part of the system won't fail. From what I've read and heard most of the recent (2019-2021) failures were due to bad batches of lifters which were out of spec in their heat treatment hardness. That was reportedly fixed before our trucks were produced. And I haven't heard of any failures in our year's units. Doesn't mean we won't but by keeping our oil changed and clean, and for me driving in L9 is my (and others) way of hopefully avoiding that type of failure.

Driving in L9 doesn't make a significant difference in fuel economy, and the transmission does still automatically start off in L1 and progress up, so it's behavior is no different. It's just that the system sees L9 as a signal that tells it DFM is not wanted/needed and so it doesn't engage.

Just an update on Range Technologies DFM disabler. I took mine off a 2023 Silverado w/5.3 and installed it in my 2025 w/6.2. Its working perfectly, no DFM, no auto start. I do remove it before oil changes at the dealer (I'm not going to do oil changes anymore). I did my first over the air update (OTA) with it installed at my gun club yesterday and everything went smoothly, no problems. So from here on out I think everything is OK and I'm going to leave it installed. I would recommend you install it, enjoy your truck, and just drive it. No DFM, no auto start and no need to cycle through to L9 anymore.

[Jimbeau]

Great info! Had no idea that running in L9 would disable the DFM. I tried it today. Couldn’t tell any difference in the way it runs. Still a low RPM. 

[TrueBlue]

Thanks @Bikerjon I will install it at some point.

When I changed my oil a couple of weeks ago I took a look up there with my truck on ramps, and believe I can access the ECM connector without even peeling the fender liner back. From the looks of things it'll take me longer to get my stepladder and remove the negative batt cable than it will to install the Range Unit.

I've only had my truck in twice, the first time when the CEL came on for the Aero Shutters not cycling. And the second time when they had the recall on the brake and the sound system software updates And each time I had to remove the A pillar cover and reconnect the antennas behind it before doing so. And then disconnect them again afterwards. The second time the light came on the code was again for the aero shutters and I just waited it out. It self corrected after the temps warmed and they were able to cycle again. I do my own oil changes but I'm still stalling on the disabler until I get a bit more confident about not having to take the truck in again anytime soon.

 

Yeah Jimbeau, I doubt that the L10 or D gear would give even a full mpg to the fuel economy. Especially for those of us who don't habitually run the truck to high revs. I could be wrong, and eventually I'll find out for sure when I install the disabler and just put it in D everytime.

Edited November 22, 2025 by TrueBlue

[PunchT37]

My brother has a 2024 L84 with 41,000 miles on it now. No problems. That’s the one I based my decision on to buy. 

[Jimbeau]

Day 2 of running in L9 instead of drive. This was my “no radio day” observation. Focused on engine tone, acceleration, and feel.
-The drivetrain seems to decelerate more rapidly when I let off the gas pedal than when the transmission is in drive. It’s as if it’s being geared down a bit more during the deceleration.

-To be expected, I notice a hint of a difference in tone due to all cylinders operating.
-It may have a bit more torque on the initial touch of the gas pedal during casual accelerations. I didn’t have the opportunity for any rapid accelerations. 
-At idle (stopped while in L9) there appears to be an ever so slight vibration felt throughout the truck. I’m talking almost unperceivable but it’s there. It’s a mid to high frequency vibration felt while holding it stopped with the brake. 
-In drive (not L9) I feel zero vibrations regardless of conditions. So smooth! 

 

My guess is that the DFM must help this engine balance itself out when active. I can’t even tell things running. Really amazing! It’s such a shame this technology hasn’t been more reliable. 

[TrueBlue]

The factory shutter valve, or whatever it's called will also add to the dynamic of what you're listening for and feeling. I removed mine when I had the exhaust changed. I do like hearing the motor, and you're right in that you can actually hear it downshift moreso in L9 than otherwise. My truck sounds like a '70s V8, which how I like it. Not too loud but plenty loud enough when I put my foot into it. And I can hear it at all times which I also wanted.

 

I'm skeptical about DFM adding anything to the balance. More likely what you're feeling there is just a different or lesser "punch" due to it suddenly becoming a six cylinder when it activates. At that point two sets of the moving parts are just coming along for the ride so to speak, and instead not adding to the cause of the crank rotation.

Edited November 22, 2025 by TrueBlue

[PunchT37]

I drive mine in D all the time. That DFM is seemless. Smooth as glass. I can`t tell or hear it dropping cyls. The short oil path to the lifter and the computer speed on these L84`s should prove to at least be better than the AFM versions.

[outrag1]

I've got a 24 with the 5.3 and about 11500 miles.  I do the first oil change early to get rid of break in material at about 1000 miles.  Next oil change was at about 4k miles with the recommended 0w20 but switched to Amsoil.  I did one more oil change at about 8K miles but this time switched it up to RedLine 5w30.  Since the switchover on the last oil change, my pressure has been solid and there is no decline in oil level when I recently checked.  I'll probably continue doing what I'm doing as it seems to be running great.