I took my truck back for the 3rd time for this sound. The mechanic came out to ask how it has been who is the one who always works on it. I asked him what exactly is the process in that tech bulletin. He said just what i have read online. Jack the truck like 1ft off the ground in the front only, let it run close to an hour with the overfill cap off. He said yes you will lose coolant since it will bubble out, not a lot but definitely some, so make sure you have some if you plan on doing this several times at home.
Yes said the tried it a different way which did not yield any better results. He said since the thermostat is electronic they drove around with their little computer plugged in and the thermostats only opens 60-70% of the way at normal operating temp since we are not towing etc.. They said they told the computer to open it at 100% so there was no restricted flow, but that really didn't help much either. He said it is just a bad design with the reservoir placement and the hoses going into the heater core which make it susceptible to air.
Lot of info but it is good that they have made some effort to fix. I just don't understand how some people have did this once in their garage and it is good and mine has been in several times!