The following results are from the factory-filled 75w140 in rear differential of my recently purchased '99 F350. This truck has the Sterling 10.5" rear axle with a traction-lok carrier. Analysis by Schaeffer's.
Copper-2
Iron-1315
Chromium-2
Aluminum-2
Lead-0
Moly-5
Phos-2015
Zinc-187
Magnesium-10
Calcium-28
Sodium-23
Silicon-165
Potassium-5
Water-none
Sulfur-6
Oxidation-41
Nitration-7
Visc CST-22.64
Copper-2
Iron-1315
Chromium-2
Aluminum-2
Lead-0
Moly-5
Phos-2015
Zinc-187
Magnesium-10
Calcium-28
Sodium-23
Silicon-165
Potassium-5
Water-none
Sulfur-6
Oxidation-41
Nitration-7
Visc CST-22.64