Completely different differential as ours is sourced from GKN and is mechanically different.
There doesn't need to be acknowledgment from GM or a TSB as you're having an issue that can be reproduced. TSB's are issued when there are enough failures and help guide the dealer toward the correct repair.
My tech sent an email to GM's technical line and was told to replace the differential under warranty. My pinion seal was leaking and that's serviceable in the field. The diff is not field-serviceable so it got replaced.
Sounds like you need a new service writer or escalate it to the service manager.
Appreciate the reply. As far as I know they have contacted the technical line, that's where the Corvette reference came in. He said it'll more than likely get replaced, they just have to go through all the steps they were given to diagnose it.
I'm going to let them do their thing, I used to be a tech at a dealership and getting through all the red tape takes time. I just figured there might be more out there with the issue... not on this forum...and maybe GM had taken notice to put something in writing.
One question for you though since you've been through this process... What kind of warranty came with the repair?