Update on my TSB A/C Fix fiasco. It's been about 5 weeks since TSB was done, At the time, I drove the truck home and parked it for a few days. I noticed it was leaking coolant somewhere on the front passenger side (carpet was soaked), so I sent it back via rollback to the dealer. Didn't want to drive it as the coolant reservoir was empty, and I had no idea how much coolant had leaked out (it was parked on the grass).
Within 1 hour of the truck being hauled off, they called me and said they're ordering a new heater core and carpet set. So the dash has to come out again, and so does the rest of the interior. Good times.
The service manager said they liked to replace the heater core when they do the TSB, but at the time the heater core was on back-order and they thought I needed the truck back. At no point in any of my convo's with the service writer did they indicate they liked to replace the heater core too, giving me the option to put off the initial repair. So, much of this was preventable, which is irritating. So be forwarded.
Looking at the heater core, the inlet and outlet pipes are simply crimped on. So my guess is when the tech is wrangling the heater core out of the dash/firewall to replace the blend box, those outlet pipes gets damage. Inspecting mine, one of the outlet pipe was clearly "loose". Although it was still mounted, you could wiggle it. Missed pics for the dash out phase, but got some with the interior out when they were sopping up the antifreeze.