newdude

DFM is just the name of the newest cylinder deactivation. DFM and AFM are in the basics the same thing, difference is DFM has all 8 cylinders equipped with active lifters, AFM its only 4 cylinders. DFM can also alter the number of cylinders in operation from all 8 to as little as 2, where AFM is the same 4 cylinders can deactivate, V8 or V4 mode. Both systems use the same exact lifters. The issue with both systems is the possibility of active lifter failure. The internal spring and locking pin mechanism is the most common culprit. Control solenoid failure is a possibility as well but not as common. Oil aeration, a miss timing of the solenoid sending oil to collapse the locking pin, a miss timing of the solenoid closing and taking oil away causing the lifter to lock back in prematurely, lifter sticking in the bore. Like all other oil operated systems in modern engines, clean oil and good oil pressure are a MUST in their operation. I'd say a majority of the ones we've done all were on high oil drain interval vehicles, so over 6,000mi between oil changes, but I can't say that 100% a shorter drain interval would stop lifter failure. I have no further data to support that. The most recent rash of lifter issues was a production issue. GM had a known batch of bad lifters made from September 2020 to March 2021. This is the reason for the latest bulletin on the 2020-2021 trucks.

We've sold a bunch, zero in the field factory DFM disabled failures that I can report. SupremePizza said "yes" on the first page, I replied to him to give any recent examples, never responded. So as I see it, until there's one witnessed at a dealer from a tech and they posted somewhere online about it, or an owner reports it in the field, its zero on here so far. Lifter isn't deactivating so odds of failure go to near zero. Is it possible still for one to fail without actuation? Yes. But again, super low odds. Saw one in the 14-19 Facebook group who had a Range or was tuned out and had a lifter still go.

GM is showing an unknown stock on them at one warehouse. They are on National Control so if the dealer put a SPAC case on it, all they can do is wait until GM releases it to them. Not sure if you are aware of all the world issues going on right now, you know...people quitting, boats stuck at port, lots on sick leave for COVID...EVERYONE is waiting for parts, vehicles, etc. Its not just you.

Gotcha. You could start simple, get 2 quarts of fresh GM AutoTrak II Fluid (the blue stuff) and drain out what's in the case. I suppose there is a possibility that old or wrong fluid could be making the clutches send power to the front when it shouldn't. The more likely scenarios would be that the encoder motor (transfer case actuator) isn't shifting the transfer case correctly and is only giving you 4HI. There could be an issue with the transfer case control module, but you'd be seeing codes with that. You are getting driving symptoms of being in 4HI, so it sounds like the front axle is actuating properly, so that leads me to think your issue is in the transfer case.

Are you saying that in AUTO you are getting binding when turning in the front end like its in 4HI?

NOT in the glovebox. The QR is in the driver's door jamb.

They did make a couple changes, mainly the biggest being the updated torque converter. The 19+up 8 speeds have a CPVA or Centrifugal Pendulum Vibration Absorber torque converter that initially debuted in the 6L50 behind the 2.8 Duramax for 2016+ Colorado/Canyon. Chevrolet Introduces Colorado Duramax Diesel (gm.com)

Yea GM has there transitionals kinda strange. Most everyone just makes their refresh or new model become a new model year, GM likes to split it up like they've always done. Give it another month or month and a half you should see the build and price pop up and the reg standard bed will pop up.

Yea GM changed it. We've had 2 come in the last 6 months and both didn't have LED. Shows the same in the parts catalog. 2020 and 2021 had LED, now its incandescent bulb.

Dealer can only program for factory sizes. Programmer, tuner, calibrator, etc. are your options.

Welcome! That is one hottt truck. I love the factory look under the hood you've got going there with that big ol snail. Looks like it rolled off the assembly line like that. The outside is great too, nice clean look yet just the right amount of pop to it with the painted bumpers and the wheels. If the sticker on the hood is not deceiving me, 6.0 swapped? Do you have a 4L80 behind it or a super built 4L60/70?

Red for the LEDs. Red. White LEDs create a washed out color due to their 5000K-6000K light color. Red or White LED bulb behind a Red Lens? (with video demonstration) : Automotive News by ABD.co.uk (autobulbsdirect.co.uk)

No deletes for the 3.0. Bumper to bumper is 3yr/36K, powertrain is 5yr/100K.

Yep. The airbox is the same, the filter is the only difference between the standard and high capacity. High capacity has more pleats for filtering. You can put the HC filter in a truck that didn't come with it.

Could be. I'd check the trailer plug for any corrosion in the terminals. We had a truck with a very similar scenario but no cap on the truck. Had a corroded turn signal terminal on the 7 way trailer plug. If they tied the cap into the trailer plug that could have set it off too. The trailer lighting control module I think can get pissed off easily hence why the corroded trailer plug on the one we had made the driver's signal work all sorts of strange with the lights on and off. Wouldn't even flash sometimes at all, just stay full lit and the indicator in the dash was on most of the time solid and not blinking.