To check transmission oil level:
Put the car on a level surface.
Leave the engine running, in park
Pull the dip-stick.
The 30-80 are for cold/hot condition. If the car has been running for a while and has reached its normal operating temperature, take the reading versus the 80 mark.
Your shifting problem could be a faulty/disconnected modulator (located on the left side of the transmission)

jackD