Ford Falcon: Ruptured oil cooler

I have a 2009 FG Falcon with only 61,000km on the clock. I bought the car from a dealer and have always had it serviced by the dealer. The other day it started making strange sounds and the revs started jumping. I took it to the dealer where the foreman mechanic gave a wry smile and said "I don't even need to take this for a test drive, I know what it will be." He lifted the bonnet and checked the transmission fluid and showed me that it was milky. He explained that the oil cooler had ruptured contaminating all my fluids and trashing my 6-speed auto gearbox. They are charging me $7300 for repairs, which includes an "exchange" gearbox and presumably a new oil cooler – but most likely in the same configuration. I've since come to realize that this is a design fault that was never recalled. I am really quite upset this has been a known issue for many years, and I feel cheated. I look after my car, I don't drive many kilometres, I don't hoon around, and the car is always in a lock-up garage. Having to fork out $7k+ in repairs due to a design fault regardless of warranty periods fails my pub test. The trade-in value is around the same as the repair cost. After all these years of the oil cooler being a well documented and well known fault, I would like to know where it has got up to in terms of consumer complaints/or class actions. What options have others pursued on this matter? Do I just smile and hand over my hard-earned?