5.3 A8 noticeable shudder when in AFM Mode

[NW-99SS]

Got a brand new work truck from the company last month.  Silverado LT True North Edition (Canada thing), CCSB, 5.3L, A8.

 

I have already noticed a shudder or vibration when the engine cuts power to cylinders...in the previous Gen, this would have been V4 mode, but in these new trucks, GM says they can run on a varying amount of cylinders depending on load, speed, etc.

 

Anyway, curious if anyone else has already experienced this?

[Limelight]

DFM.  

[Wiggums]

As Limelight pointed out, it's now called DFM.

I feel it once in a while, feels like it's jumping into overdrive and there's a little shudder in the meantime. That happens when I hit 65 and am not accelerating.

It's something you need to get used to. It's supposedly much better than AFM and Chevrolet says more reliable too.

[econometrics]

1700 miles on mine and haven’t ever felt it. And I’ve tried pretty hard to notice it, too. 

[NW-99SS]

Alright DFM it is...very noticeable at steady 50 mph or 65 mph when it's activated.  Not a fan.

[z1boss]

1 hour ago, NW-99SS said:

Alright DFM it is...very noticeable at steady 50 mph or 65 mph when it's activated.  Not a fan.

 

I have 17k miles on my Trailboss with the 5.3 A8 DFM engine.  Absolutely zero issues related to the motor.  You must have a defective one.  The DFM is 1000% smoother and unnoticeable compared to the older AFM engines

[NW-99SS]

10 minutes ago, z1boss said:

 

I have 17k miles on my Trailboss with the 5.3 A8 DFM engine.  Absolutely zero issues related to the motor.  You must have a defective one.  The DFM is 1000% smoother and unnoticeable compared to the older AFM engines

This is what I'm worried about.

[K455]

On 5/15/2019 at 10:20 AM, z1boss said:

 

I have 17k miles on my Trailboss with the 5.3 A8 DFM engine.  Absolutely zero issues related to the motor.  You must have a defective one.  The DFM is 1000% smoother and unnoticeable compared to the older AFM engines

I have the custom TB Z71 with AFM,are you sure you have DFM?just curious at 700 miles I plugged in a new Range tech,it was smooth before that,but I want all 8 all the time.

[swathdiver]

2019s are running both L82s and L84s, AFM and DFM motors.  

[ILSilverado]

Range Technology is currently developing an OBD2 Port unit to keep the DFM in 8cly mode all the time as well as permanently disable start stop. should be out in a few weeks.

[z1boss]

1 hour ago, K455 said:

I have the custom TB Z71 with AFM,are you sure you have DFM?just curious at 700 miles I plugged in a new Range tech,it was smooth before that,but I want all 8 all the time.

I have an LT Trailboss so I have the new DFM on my 5.3

[BlancoSilverado]

3 hours ago, swathdiver said:

2019s are running both L82s and L84s, AFM and DFM motors.  

This is correct, If you have the 6-Speed then you have the L82 with AFM (only down to 4 cylinders). If you have the 8-speed then you have the L84 with DFM. I made sure that i purchased with the new gen motor. 

[HondaHawkGT]

DFM is 10 times smoother than AFM was in my 2014, which itself was supposedly a huge improvement over AFM in the GMT900's. I'm okay with DFM considering I average over 24 MPG on long highway runs at 60-65 MPH. It's very difficult to notice unless I focus on it very carefully.

[NW-99SS]

On ‎5‎/‎18‎/‎2019 at 12:25 AM, HondaHawkGT said:

DFM is 10 times smoother than AFM was in my 2014, which itself was supposedly a huge improvement over AFM in the GMT900's. I'm okay with DFM considering I average over 24 MPG on long highway runs at 60-65 MPH. It's very difficult to notice unless I focus on it very carefully.

This is what makes me thing something is wrong with my 2019 work truck.  Although I am comparing a '19 - 5.3 to a '17 - 6.2

 

My '17 Denali is smooth and nearly imperceptible, I can tell every time the DFM kicks in on the 2019.

[Wiggums]

I am not a hard accelerator.. and it takes me a while to get up to 65 then I ease off the gas. I can feel it. You have to do it slowly. It takes me about 20 seconds to get up to 60 then another 10 or 15 seconds to get up to 65, I like doing it that way.. since I am taking a while from 60 to 65, I can feel it. Gotta be really easy on the gas. I usually feel it when I'm going downhill. I don't think I'd have felt it if I wasn't looking for it.