Where to find diff oil?


Just wondering if anybody could recommend where i can buy the SAE 80W/90 diff oil specified for the Fourtrak f78?




Diff oil is better known as hypoid gear oil, this is available from car shops and motor factors, it is generally available in 75/90 these days, and this is suitable for your vehicle.
If you are changing it, buy 5 litre cans as well as a 1 litre top up bottle with the extended spout to fill the diffs up.