I replaced the factory 3.91 ratio '741 gearset with a Richmond 4.10 ratio '742 gearset, but gear oil continues to 'vent'..grrh!

Since the factory calls for 4 pints I used 1.8L, which is 4 pints, which is 2 quarts. But so far having driven around for about 500 miles I keep on watching the axle vent 'percolate' and dump excess gear oil out. It is worse when I put on some highway miles. I do not baby the darn thing, my last time out was an hour long run @ 120 KM/h (75 M/h) which meant the motor was turning a good 4K. The center section temp never went over 75degC (165-170F), so I think I have been OK there.

Given that Richmond recommends changing the original gear oil out at the 500 mile 'break-in' mark I emptied the stuff out with the suction pump. I measured a total of 1.6L, which is about 3.4 pint (1.7 quart), granted this way of draining it is far from precise.

Alright, so any advice just how much I should re-fill with?

It took me some time to wipe down the fuel tank, suspension pieces (shocks mostly)...just a nuisance, but the factory 2 quart fill was too much (that included the SG additive). So I'm thinking I need a tad less, obviously I do not want to go too low (is there a known too-low value?).