Does anyone know why the Ford V828A takes 75W140 gear oil and the 828B takes 75W90? Both are 8.8 open differentials with a 3.55 ratio. Is one axle more heavy duty than the other?

 

the 80 w 90 is an old spec... the new oil spec is 75 w 140... they all use that now.. IF you have a LS clutch, you need a bottle of friction modifier added. You can get the 75W 140 at WAl Mart for a decent price.. seems quite high at most places.