SSsierra

I had exact same problem 2020 Sierra 1500 crew cab 5.3 4x4 with 10 spd. 4 trips to dealer and Dealer had no diagnostics said was operating as designed, they tried blaming the Dfm. I did tons of research which I found out it was the driveline operating angle. I had my ride height driveline angle measurements taken by a 4x4 shop trans angle was 420, drive safe was 420, rear pion angle was 0.65. I ordered a 2 degree angle shim fat end facing towards the rear and wha Leah perfect no more vibration

Winks did you have to drill holes for install?

I have the 5.3 with 10spd and has the same issue. I have measured the driveline angles and it is out of spec. On my 2020 Sierra they didn’t use any rear leafspring blocks or shims as they did on previous years

Did anyone try the range or the pulsar or see if it cures the low speed shutter with the 10 spd

Did you get a chance to flip the factory shims? Do you mean by saying you think they installed them backwards meaning the fat part of the shim was towards the rear of the truck.

Interesting my 2020 doesn’t have the leaf spring block nor does it have this 1/4” shim either and I have a low speed vibration between 28-10 mph. I am thinking this forward 1/4” shim would fix my pow speed vibration

Good to hear you got it resolved, I wish I could remove the shims and be done with it but yesterday I got under my truck to check for shims and there isn’t any shims nor did I see a factory block in rear

I am getting this issue and I do not have the shims. I have 2020 Sierra 5.3/with 10 spd tranny

I have the 5.3 /10 speed and I also definitely have this issue, I think it is the driveline also

I have a 2020 Sierra 5.3 with 10 spd tranny and I have the low speed shudder. Awaiting recommendations from gm pico scope findings. I really think it is a pinion angle issue

I have a 2020 sierra crew cab with 5.3, 10 spd trans and having low speed vibration 28-10 mph (deceleration or acceleration). I took vehicle to dealership on Monday. Two days later dealership called and stated all the test they performed (DFM, Trans mount ect..) was working as design and nothing could be found to cause issue. During this call I stated to service manager what was I suppose to do just live with this issue. I also stated that i was on GM truck forums and there where numerous identical issues, do I need to have a GM-Tech reach out to them? Service manager said let me talk to shop foreman/supervisor and see if there is anything he can do. Next day service manager was having another Pico scope test done to try and find issue. UPDATE; Shop foreman/supervisor called GM-Tech and they requested another Pico Scope be performed and to send them the results. Currently waiting on GM-Tech for guidance from Pico Scope results, should hear back from GM next week. I requested a loaner vehicle and dealership stated i could come get my truck and that it was safe to drive until they get the guidance from GM next week. Will update when GM gives guidance.

I am in the right thread, most on this thread are talking 2019-2020 issues with 5:3 and 6.2 with 10 spd

I have a 2020 sierra crew cab with 5.3, 10 spd trans and having low speed vibration 28-10 mph (deceleration or acceleration). I took vehicle to dealership on Monday. Two days later dealership called and stated all the test they performed (DFM, Trans mount ect..) was working as design and nothing could be found to cause issue. During this call I stated to service manager what was I suppose to do just live with this issue. I also stated that i was on GM truck forums and there where numerous identical issues, do I need to have a GM-Tech reach out to them? Service manager said let me talk to shop foreman/supervisor and see if there is anything he can do. Next day service manager was having another Pico scope test done to try and find issue. UPDATE; Shop foreman/supervisor called GM-Tech and they requested another Pico Scope be performed and to send them the results. Currently waiting on GM-Tech for guidance from Pico Scope results, should hear back from GM next week. I requested a loaner vehicle and dealership stated i could come get my truck and that it was safe to drive until they get the guidance from GM next week. Will update when GM gives guidance.

I traded my 2014 5.3 with 6 psd for a 2020 5.3 with a 10 psd and the 2020 is much responsive and quicker than my 2014 was and it had a custom tune

Rick did you find any more info on chrome fog light sussound? I have a 2020 SLE and wanting to add fog lights with chrome surround