I’m going to replace my rear spring in a few weeks and while under the car, I plan to fix a pesky differential leak.  The leak is from the front pinion seal but it never drops a drop on the floor of the garage.  It just coats the underside of the car.  "Diff oil seems to make a good undercoat remover."  Is this how a pinion seal leak starts and will it get worse?  I did check the differential plastic vent this evening and it was kind of gummed up.  I removed the cap and poked a wire down it and noticed a little resistance at first but I’m not sure it was truly plugged.  I plan to clean things up a bit around the pinion and floor pan then check for fresh oil over the next few weeks. 

Thanks for the replys.  Any gotchas to look out for when replacing the pinion seal?  I have read a few post and service manuals that cover it and the trickiest part seems to be the tightening of the Pinion nut.  Is it as simple as marking the nut/pinion and counting the number of threads showing before removal.  Then tighten back to that same spot?  Or do I need t dial torque wrench or spring gage to measure the torque required to start the diff turning.

Mkaap7879, a big thanks for the angle iron tip.  I made one as you suggested and had no problems removing the pinion nut.

 

 

It’s been a few days with no leaks so far, only time will tell.  Back on the road for now