Shudder Condition When Coasting to a Stop.

[crj19]

https://gm-techlink.com/?p=15387

 

Some 2021 Silverado 1500 and Sierra 1500 trucks equipped with the 5.3L V8 (RPO L84) and 10L80 10-speed automatic transmission (RPO MQB), excluding models with RPO YK9, may have a shudder condition when coasting to a stop between 15—13 mph (24—21 km/h). (Fig. 10) The shudder may feel similar to driving over rumble strips on the pavement when the vehicle is coming to a stop.

 

Fig. 10

 

During diagnosis, the shudder condition will be easily duplicated every time the vehicle coasts at the affected speeds. The shudder may be due to the reduction in the number of cylinders firing during deceleration, which may lead to structure-borne noise, vibration and harshness (NVH) on some vehicles when coasting to a stop between 15—13 mph (24—21 km/h).

If the shudder condition at the affected speeds is confirmed, reprogram the Engine Control Module (ECM) with the latest calibration available. Do not replace any parts for this condition.

It will also be necessary to perform the Crankshaft Position Variation Learn procedure covered in the appropriate Service Information once the ECM has been updated. The crankshaft position sensor variation is used to calculate reference period errors caused by slight tolerance variations in the crankshaft and crankshaft positon sensor, which allows the ECM to accurately compensate for reference period variations and detect misfire events over a wider range of engine speed and load. If the Crankshaft Position Variation Learn procedure is not completed, the ECM calibration will not provide the desired results.

TIP: Always verify that the VIN displayed in the left-side drop-down menu in Techline Connect and the top-center window match the VIN plate of the vehicle to be programmed prior to using Service Programming System 2 (SPS2) for programming or reprogramming a module. (Fig. 11)

 

[kmeleon]

9 hours ago, crj19 said:

https://gm-techlink.com/?p=15387

 

Some 2021 Silverado 1500 and Sierra 1500 trucks equipped with the 5.3L V8 (RPO L84) and 10L80 10-speed automatic transmission (RPO MQB), excluding models with RPO YK9, may have a shudder condition when coasting to a stop between 15—13 mph (24—21 km/h). (Fig. 10) The shudder may feel similar to driving over rumble strips on the pavement when the vehicle is coming to a stop.

 

Fig. 10

 

During diagnosis, the shudder condition will be easily duplicated every time the vehicle coasts at the affected speeds. The shudder may be due to the reduction in the number of cylinders firing during deceleration, which may lead to structure-borne noise, vibration and harshness (NVH) on some vehicles when coasting to a stop between 15—13 mph (24—21 km/h).

If the shudder condition at the affected speeds is confirmed, reprogram the Engine Control Module (ECM) with the latest calibration available. Do not replace any parts for this condition.

It will also be necessary to perform the Crankshaft Position Variation Learn procedure covered in the appropriate Service Information once the ECM has been updated. The crankshaft position sensor variation is used to calculate reference period errors caused by slight tolerance variations in the crankshaft and crankshaft positon sensor, which allows the ECM to accurately compensate for reference period variations and detect misfire events over a wider range of engine speed and load. If the Crankshaft Position Variation Learn procedure is not completed, the ECM calibration will not provide the desired results.

TIP: Always verify that the VIN displayed in the left-side drop-down menu in Techline Connect and the top-center window match the VIN plate of the vehicle to be programmed prior to using Service Programming System 2 (SPS2) for programming or reprogramming a module. (Fig. 11)

 

Thanks, my truck definetely needs this. 

[Mcropper514]

Thanks for this as well.  It's been driving me crazy trying to figure out what this is.

I need an oil change and will be asking them to look at it this as well.

[JasonAnderson]

The shudder issue in the 2021 Silverado and Sierra 1500 trucks with the 5.3L V8 and 10-speed transmission sounds quite concerning. I’ve heard from others experiencing the same problem, and it does feel like driving over rumble strips, significantly when slowing down. If you're facing this, it might be worth contacting your dealer for a diagnostic.

[Innytrag]

I know it's been a while, but that shudder you feel when coasting to a stop can be annoying. It could be worn brake pads or rotors, which can cause vibrations when you slow down. Sometimes, it can be the tires, too, especially if they’re unevenly worn. Have you checked those out?
Another thing to think about is the suspension or even the drivetrain. If you’ve got some play in the joints or bushings, that could also cause a little shudder. It’s a good idea to have a mechanic take a look, especially if you’re unsure.
Also, if you’re into DIY, rubber compression molding can be a neat way to help with those little vibrations. It’s something to consider if you want to tackle it yourself.

Edited October 7 by Innytrag