Severe oil leak happen while driving. Engine still runs but can't locate where leak is coming from. Any Ideas or solutions beside paying 100s of dollars.

Common area for oil leaks would be from the oil filter, oil line to the cooler attached to the radiator and the other place that is most common would be a faulty oil pressure sending unit.
When the oil pressure sending unit goes bad, oil will leak from the unit. It's made of a metal fitting and plastic top and the plastic will tend to crack after a few long years from the heat making them brittle.
Inspect your oil pressure sending unit and replace if any sign of oil, You can pick up the unit at Auto Zone and can give you the step by step instructions to get the job done with common tools. They would also be glad to help you find where the leak is coming from free of charge.
Thank you for using fixya and if it's your transmission that is leaking, don't drive it if the level is low and take note transmission fluid is flammable and will catch fire from the heat of the exhaust.