I have a '93 Eplorer 4x4 and a couple of days ago I noticed the smell
of gear oil when I'm around the rear but never saw and drips or satins
on the driveway.  i was hoping it was my imagination, but today toward
the end of a long ride i began to smell burning when accelerating hard
up a hill.  I got under there and noticed some oil had been leaking out
where the shaft goes in to the differential in the rear.  i think the
burning smell was from the oil flying off the shaft yoke and on to the
exhaust.  At least i hope so. Does this sound like a pinion seal?  if
so is it a reasonable DIY job on this car?  What about trying to add a
seal softener or something to string it along or awhie?  Would
appreciate any feedback.   Never had diff problems before.  Thanks.