But would this still occur at lower speeds? Mine shimmies at 20-25mph and again 45-49mph. My 2014 Silverado has been in 3x now. Replaced the torque converter and not fixed. Today the service dept said they had 3 other Silverados in with same problem and none of them exhibited the vibration/shimmy including mine. At this point I am not happy that this problem continues to be undiagnosed.