Ford Ranger Maintaince And Repair Manual page 437

If the crankshaft rear oil seal replacement is the only operation being performed, it can be done in the vehicle
as detailed in the following procedure. If the oil seal is being replaced in conjunction with a rear main bearing
replacement, the engine must be removed from the vehicle and installed on a work stand.
1. Remove the starter.
Remove the transmission from the vehicle, following the procedures in Section 7.
2.
3. On a manual shift transmission, remove the pressure plate and cover assembly and the clutch disc
following the procedure in Section 7.
4. Remove the flywheel attaching bolts and remove the flywheel and engine rear cover plate.
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HOW TO USE THIS BOOK
Removing the rear main seal
Installing the rear main seal on the 2.9L engines
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REMOVAL & INSTALLATION