recommended oil for a 5711 back gear box and hydaulics

just wondering does it have to be 20 litres of 90 gear oil or what

no thats too thick,just use standard universal

80w/90 gear oil or universal tractor oil in 10w/30, 15w/30, 10w/40 and 15w/40 are all good. Engine oil will foam when used in the hydraulic system, so be sure its a STOU or universal oil.

80w/90 and 10w/30 are basically the same viscosity, just the gear oil viscosity is measured at average gearbox temperatures, and the 10w/30 is measured at engine operating temperature. Though the universal oil can withstand the heat of the engine, the pressure of the hydraulic system and also lube the rear end.