10-4. Appreciate it. I have torn everything apart under the hood at some point in time and never done this.

 

First change always looks bad due to the sealent they put on the gears to keep them from rusting before install( when you pull the cover you can see the sealant on the other parts). That is why the book says go 500 miles before towing to seat the ring and pinion. That wears all the sealant off and it looks milky brown/gray color in the fluid. I personally do mine every 30,000 miles. I would change it more frequent if I towed every mile. No sealant required on the gasket and it is reusuable. Wipe the bottom of the housing out and clean the magnet that is in the bottom. Torque the diff bolts down to 25 ft/lbs when reinstalling. If you do 30 ft/lbs as recommended you will chance snapping a bolt during install. Hope this helps.

 

Thanks Spooler.I do recall the isssue with snapping bolts now that you said something.

 

The grey color seen at first change is due to the gear marker paste they use to confirm proper setup at the factory. Nothing to worry about.

 

I will confirm that. Worked for DANA corp for several years building diffs and complete axles for the F450 and F550. The grease we used on the test stands to check gear pattern was yellow . Every warranty axle I ever tore down that came back in after a failure had a grey or milky tint to it. You also pick up some water from condensation from heat cycles on the axle tube.