The 1999 Ford Mustang six-cylinder uses a 3.8-liter fuel-injected engine with a rear-wheel drive system. The engine operation uses a variety of lubricated systems that call for different types of fluids. The factory recommendations for fluid types and amounts include the engine oil and transmission, rear differential and the various hydraulic systems.
Ford recommends five quarts of SAE 5w30 engine oil. The use of a synthetic or high-mileage oil of that weight reconditions the internal seals, prolonging the life of your engine. The transmission uses a standard multi-vehicle automatic transmission fluid (ATF) and fills at 14 quarts for the automatic transmission. Manual transmissions use a check hole on the side of the transmission. Fill until the fluid is no more than one-quarter inch beneath the hole.
The Mustang offers a limited-slip differential and a standard differential in the 1999 model. Both variations call for SAE 80w90 gear oil, however the limited-slip differential needs four ounces of friction modifier added to the differential. You identify the type of differential on the plate on the driver's side door or on the tag bolted to the upper-left of the differential.
The brake and clutch systems call for DOT-3 brake fluid. The power steering requires standard power steering fluid. All three use a reservoir system with fill lines. Do not fill past the fill lines when adding fluid. The systems must be bled each time a component of the system is replaced. Monitor the reservoirs closely when bleeding, and keep the reservoir at least half-full during the process.
