The first TSB to reprogram the PCM can be called the solution for the driveline growl. You can find the updated software solution by going to this site and entering your VIN.
BTW, the recalibration doesn't work either. All it does is force the truck to downshift faster when depressing the gas pedal. The truck will still lug and cause the driveline growl at 38-42 mph.
How do I know all of this......been there done that. And yes, you do need the GM district reps approval to change out the rack and pinion which BTW, is harder than pulling your own teeth.