HD90GL4.1L GEARBOX OIL is a high-quality transmission oil specially designed for classic vehicles such as the Citroën 11CV and 15CV. This oil provides excellent lubrication and protection against wear and corrosion, extending the gearbox's lifespan. With its 90 GL-4 viscosity, it is suitable for use in gearboxes that may experience high loads and temperatures. The formula ensures smooth gear shifts, minimizes noise, and prevents leaks. Ideal for car enthusiasts and collectors looking to maintain the performance and durability of their classic Citroën. Compatible with standard seals and components.