Truck back from the 4th visit at the dealer to correct the shimmy issues I'm having. Long story short, GM has notified the dealer that this is a "normal operating condition" and it will not pay for further warranty work on this problem. You read that right - GM is now saying that steering wheel shimmy is a feature, and not a defect.
It must be a widespread problem, as I drove 4 brand new trucks on the lot, and all of them had the same issue, one was better, the other three were worse.
What this really means is GM has no fix for the problem and they are trying to wash their hands of it. In all fairness the customer relations person I have been working with has been great at coordinating the dealer, field engineers and TAC to find a resolution. In the end though, TAC has indicated there is nothing else that can be done.
I recommend that everyone that has this problem call GM at 800-462-8782 and ask for the case to immediately be escalated to the Executive Customer Relations team. Don't take no for an answer. Also, since this problem seems not to matter to GM, report the issue to https://www-odi.nhtsa.dot.gov/VehicleComplaint/ as a safety concern.
I can't express how disappointed I am with GMs response to this.