Just got my truck back yesterday. They said the low speed shudder was a software issue.
A tech and their lead tech took out the truck to test the high speed shudder/rumble I feel under hard acceleration but said nothing abnormal was found/felt.
I thought I had felt a shudder at low speeds. At first I thought it was the air compressor since it always kicks on when I leave the house but last time I waited for it to turn off before I drove down the street. At 3.5 to 4.5 mph I feel a shudder/rumble. I believe it might be electric motor...