Tranmission is "shaking"

Mike262 · October 2

2021 sierra 1500 with 3.0L duramax. 40k on yhe truck.

Driving down a smooth country road, flat surface, cruise set at 55. The truck will be in a high gear. When I get to a little grade in the road, right before the truck wants to down shift, it fells like the transmission starts to shake. Not a vibration but a small shake.

Has anyone experienced the transmission shaking? It will shake enough that a passenger that does not ride in the truck often will notice it.

rrmccabe · October 3

Sounds like it might be your torque converter. If you watch the tach do you see a slight flicker up and down on the needle?

Bikerjon · October 4

5 hours ago, rrmccabe said:

Sounds like it might be your torque converter. If you watch the tach do you see a slight flicker up and down on the needle?

Mine is in the shop for the second time for the transmission. My description is "shuddering" on the 1-2 upshift under heavy throttle also the 2-3 upshift under heavy throttle. The Service Manager mentioned it could be the torque converter or possibly the VALVE BODY! I told them Do Not Disable for 3 months. They will let me know when they have a diagnosis.

redwngr · October 4

On 10/2/2024 at 3:59 PM, Mike262 said:

2021 sierra 1500 with 3.0L duramax. 40k on yhe truck.

Driving down a smooth country road, flat surface, cruise set at 55. The truck will be in a high gear. When I get to a little grade in the road, right before the truck wants to down shift, it fells like the transmission starts to shake. Not a vibration but a small shake.

Has anyone experienced the transmission shaking? It will shake enough that a passenger that does not ride in the truck often will notice it.

Take it in.

Common theme has been valve body issues, but they will have to do the diagnosis.

Powertrain coverage is 5 yr / 100,000 miles.