Disconnect the negative battery cable from the battery, then remove the air cleaner assembly. Drain the engine oil and remove the oil filter, followed by the engine cooling fan assembly and shroud. For 4WD models, remove the front axle assembly. On models through 2003, attach an engine support fixture to the engine lifting eyes adjacent to the
Exhaust Manifolds, and raise the vehicle securely on jackstands. Remove the oil level dipstick, then raise the engine slightly with the support fixture and remove the engine mount through-bolts. Continue to raise the engine gradually, ensuring no interference with engine compartment components, and when raised about two inches, place short lengths of 2x4 lumber between the motor mounts and the crossmember for safety. On 2005 and later Expedition/Navigator models, remove the four bolts/nuts and take out the front crossmember for clearance to remove the oil pan. Remove the oil pan mounting bolts and lower the pan to the frame cross member, then carefully separate the oil pan from the engine block using a large rubber mallet or a wood block and a hammer to avoid damaging the sealing surfaces. The oil pan gasket is reusable if care is taken during removal. Use a gasket scraper or putty knife to remove all traces of old gasket material and sealant from the pan and engine block, being careful not to gouge the surfaces. Clean the mating surfaces with lacquer thinner or acetone, ensuring the bolt holes in the engine block are clean. Apply a bead of RTV sealant to the four corner seams where the rear seal retainer meets the engine block and the front cover meets the engine block. Carefully position the oil pan against the engine block and install the bolts finger tight, ensuring the gaskets haven't shifted, then tighten the bolts to the specified torque, starting at the center of the oil pan and working outward in a spiral pattern. The remaining steps are the reverse of removal, and remember to refill the engine with oil before starting it. Finally, start the engine and check carefully for oil leaks at the oil pan, driving the vehicle and checking again.