[njsteve]

So I took the old gal out for a 100 mile trip today with the new diff fluid in to see if it helped as I was going to take a new sample and send it back to Blackstone.

I got back home and put her on jackstands and drained all the fluid out. While I was doing that and rotating the wheels to get any leftover gearlube off the gears I could hear a "tinkling" and "clicking" sound inside the differential. Sounded just like busted roller bearing with a broken cage and the roller shifting into place after a short movement.

So out comes the old rear and in goes the NOS 1994 differential that I've been saving for 28 years. To get ready, I dragged it out to the garage and set it up to drain the old clean fluid out. It looked nice and amber-colored until the last of it was coming out and then a lot of yellow marking compound was coming with the fluid. Can't get any "newer" than that. I'll let it drip over night and then refill with new 75W140 and additive made in the 21st century, versus the old pre-turn of the century stuff that came out.

Too bad the service replacement Dana 44 differentials didn't come with drain plugs like the assembly line 92/93 units.