<VV> axle question

[judynrandy at comcast.net]

I've uncovered a bit of a quirky situation while working on a bone stock '65 monza 4/dr w 110/pg.  why is it that the '65 shop manual calls for "4 1/2" pints of gear lube, but when you go to add that much only 3 1/2 pints fit in the diff before it comes pouring back out the fill hole?   Yes, the car was level when added.  This amount is precisely half way between the "add" and "fill" marks  on the dipstick. 
      Comments or explanations???? 





Randy Capn Hook 

65 monza 4dr 110/pg 

63 ragtop  84/pg