id drain it and put in fresh DEXRON VI (6)
the 3speed has no drain,so....
right side there is the manual lever, and PRNDL switch on end, cable shifted
http://www.fixkick.com/tranny/slush/slid...age_9.html
the oil there may be from leaking distributor 0-rings. down to here easy .
the kick down cable can be loose. and leak
http://www.fixkick.com/slush-pump.html#3L30-leaks
the vacuum mod valve(rear of main case) can leak too, if oil drips from its vacuum nipple its bad.
most folks add drain plug , during first drain and fill. a kit sold
the filter is here
http://www.fixkick.com/tranny/slush/slid...ge_16.html
make sure pan is not rusted though.
is your car 2wd/ if yes, the governor screens are more easy to clean 10x. (inside tail shaft housing)
fluid specifications Dex 6
trans has 10.5 pints (5.25qt) includes clutch.
drained for 1 hour 5 to 6 pints come out. so put back, 2.4qt and top off to 3qt
my wild guess.12years, drained. the box is bone dry, and clutch 1/2 full
even 4qt.lost.... over time, worst case.
leaving very little 1.25qt. dont run the engine like this or wreck the front tranny oil pump.
good luck amigo.