thanks for all of the advice on maintenece from my plug and wires question.I did what you suggested and pulled the front diff fill plug and here is what i found. The fluid was within reach, was dark grey in color but no signs of froth or water that i could tell.It did seam a little thin to me but that may be typical.So let me know what you think.
looks like you have some molly grease in your gear oil but not a whole lot, check for gear oil in the knuckle (open the square plug)
If you have gear oil in the knuckle then you need to do a birfrapack so you can replace the inner axel seal, if you do not have any gear oil in the knuckle then just change the diff fluid and delete the evil vent flapper valve to keep grease from getting sucked into the gear oil
gear oil in the knuckle is generally acompanied by a "birf soup", a mix of gear oil and grease coming out of the wiper seals.
If you let this go on for to long all of the grease will be washed away eentually destroying the birf trunion bearings and if the diff is allowed to get low also the differential,
thsi is what happens of you let it go to far. no grease left and broken parts.
