I am in the same situation that you have described with the automatic transmission requiring replacement in my 2010 Holden Cruze. I am fed up with Holden as they missed this problem and a small transmission leak, and apart from one service it has been always been done by them. I had it towed to a nearby mechanic so can I still go to Holden and ask them to contribute towards the cost of the transmission?
Yes, I believe you can, and should approach Holden with a request to contribute to the cost of replacing the transmission, perhaps even to cover the whole cost of the job. It is a flaw with the transmission, as we have seen with so many others with that model Cruze. Go directly to Holden’s customer service people and lodge a claim. But you will have trouble with getting money from Holden if your mechanic has done any work on the car.