hey aussieken! i have too a kyosho monster truck but not the giga ! the mad force! our trucks use a lof of same parts and one of the are the diffs! the diffs that use kyosho trucks are the same with the inferno so you can use silicone oil! in my mad force i use 7.000wt in front and 20.000wt kyosho oils in the rear! to find the best oils for your diffs try a lot and then you will find what u suit! and a tip for kyosho diffs go with 4 bevel gears! also join the : www.kyoshomonster.com i have join this site is awesome for who has kyosho truck we will help you a lot!