In the 1970s, operating a bulldozer or agricultural tractor meant managing three separate fluids: engine oil, transmission fluid, and hydraulic oil. Each had different viscosity grades, change intervals, and performance requirements. This created logistical nightmares for fleet managers and increased the risk of costly cross-contamination errors.
The breakthrough came when Caterpillar developed the TO-4 specification—a universal tractor transmission oil that could handle the extreme pressures of hydraulic systems, the friction requirements of wet brakes, and the gear protection needs of powershift transmissions, all in one formulation. This wasn't just convenience; it was engineering genius. The challenge? Creating a fluid that remains stable across temperature extremes while providing the right friction coefficients for both slipping clutches and non-slip hydraulics.
Modern semi-synthetic formulations like HEXOL TORSION HYDROGEAR TO-4 continue this legacy, meeting demanding specs from Caterpillar, Allison, and Komatsu in a single pour.
