Fluids.
The fluid in your PT&T system is under extreme pressure that can cause molecular shear, which tears apart the fluid’s molecules, resulting in a drastic loss of lubricity. Don’t use substitute oils like motor oil or power steering fluid. Yamaha Performance Power Trim & Tilt Fluid is specially formulated to tolerate a specific amount of water ingestion and still maintain proper operation, all while withstanding extreme pressures. It also contains special anti-foaming agents the others don’t, to maintain critical lubricity.
You can use Dextron II or III but mix with the existing fluid...