FLUID LEAK DIAGNOSIS
S ECTION
II
2–1. FINDING THE LEAK a. Identify the fluid. 1. Determine if the fluid is engine oil, automatic transmission fluid, or hydraulic fluid from a specific vehicle system. 2. Operate the vehicle to reach normal operating temperature and park the vehicle. Inspect the vehicle to identify the source of the leak. b. Typical Leak Points and Causes. Refer to the following list for possible points of fluid leaks and their causes. • Transmission mating surfaces: — Attaching bolts not correctly tightened — Improperly installed or damaged gasket — Mounting face damaged • Housing leak: — Filler pipe or plug seal damaged or missing — Filler pipe bracket dislocated — Oil cooler connector fittings loose or damaged — Output shaft seals worn-out or damaged — Pressure port plugs loose — Porous casting • Leak at converter end: — Converter seal damaged — Seal lip cut (check converter hub for damage) — Garter spring missing from seal — Converter leak in weld area — Porous casting • Fluid comes out of fill tube: — Overfilled — incorrect dipstick — Plugged vent (breather) — Water or coolant in fluid — fluid will appear milky — Drain-back holes plugged 27
