A couple thoughts: Check your engine oil. If it is over full it probably has hydraulic fluid in it and your pump is leaking hydraulic fluid into the engine.
The other thing is I filled my BG with less than 2 gallons of Dextron 3. (less than 8 liters.) And since an R would have the same reservoir, pump and cylinder, it should hold nearly the same amount of fluid except for the hoses will be longer.