Welcome to the "WIRE" <img src="/forums/images/graemlins/cheers.gif" alt="" />
A little more info needed on your rig...
What year?
Which engine? 3.5 DOHC? 3.0 24 valve? 3.0 12 valve?
Oil pans arn't the common culprit. Usually cam seals with air curents making source location difficult.
A lot of info on here on such things as the Harmonic Balancer wrench ( homemade) needed to change seals and T belts, etc.
Enjoy...

dave h.
'89 Raider V6 5spd;Aisin Hubs;; Gen2 LS: frt. brakes, rear coils;U.C.arms;R.trailing arms;idler arm; rear LSD axle w.disc brakes ;2 battery system for Dog's fan; relocated ECU; custom bumpers;J.Baker receiver;Conferr roofrack; t-bar crank.