I just got back from hunting and noticed that the bottom of my truck is not just wet. In fact it is coated with what appears to be engine oil. All of the fluids check out fine and the coating starts at about the bellhousing. It has almost 90K on it and I have had the new clutch on the floor (about 2 years)waiting for the right moment to go in. How hard is it to replace the main seal and how much do they run? Any upgrades? How easy is this to be done in the driveway and about how long does it take? Thanks, Eric