Actually, on these cars, the transmissions have a specific oil capacity. If you fill them until it 'drizzles out', you've overfilled it. We've discussed that here a few times.

Capacity---Type A tranny. 4 speed 240---3.2 US pints

-----------Type B tranny. 4 speed 260---4 US pints

-----------5 speed 240 and 260---3.2 US pints.

Auto--------11.5 US pints

Couple of things:

1)pay attention to the FSM.Folks like me in Arizona,the book calls for 140 weight.And 20/50 in the engine.

2)Make sure the vent on the trans is clear and operational.If it is plugged,the lube/vapor would have no other place to go than the shift opening.This goes for rearends too.Except when this vent gets plugged,the oil gets pushed past gaskets &seals.