88 Spider Differential Question

["Paul Weimer" <pjweimer@domain.elided>]

I finished the brake master cylinder job this afternoon.  Mini-Vac'ed the
brake lines, all seems well although I haven't taken it down yet to drive.
While under the car I noticed that some fluid was being deposited on the
undercarriage above the rear axle.  More so to the passenger side than the
driver side.  Figuring the options to one of three:  brake fluid, gasoline
or differential lube.  Had a friend work the brakes and start the car,
nothing.  Therefore I am assuming it is differential lube.  Elected to drop
the lube (probably needs changing anyhow).  Removed the bottom plate of the
differential (where the drain plug is) and found the gasket to intact but
harder than a rock.

Rather than ordering a new gasket I am considering making one from gasket
material that I have on hand.  Is this gasket anything special or will
gasket material (the kind you can buy by the roll) be OK?

Second question:  the shop manual says the differential should be filled
with 2.75 lbs. of lube.  I've got a quart of 80/90W.  How do I convert
liquid ounces to pounds?  Should I just weigh out 2.75 pounds of this stuff
on our kitchen scale?  Thinking that must be a conversion for this but can't
find anything in all the books and manuals I have at the house.

TIA,
Paul Weimer, Ohio

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