Found it. The Liqui-Moly gear additive in my diff.
https://www.liqui-moly.com.au/produc...-oil-additive/
And here's the Total Fuel System Cleaner/Conditioner:
https://www.liqui-moly.com.au/produc...r-conditioner/
How many people swear by Mobil 1 oil? Their fuels are also A1. The site I use is a huge four bay two bowser per side layout normal petrol station - it's a well-frequented large site with exactly the same services a petrol station should have, it just happens to be 7-11 branded with Mobil fuels.
Check out Mobil's fuels (everything is additised from Special 91, Special Diesel, E10 (94 RON), Extra (95 RON) and of course Supreme 98+ with the top grade package) plus a fun video:
https://www.mobil.com.au/en/our-fuels