did all the oil fall out of the motor?  how long was it run like that?   were
there shavings when you drained some oil?  does it make a bad sound when it
runs?  if you turn it around by hand do you hear a thunk?  how's the end
play- check by grabbing the crank pulley and giving a firm push-pull.  it
should only move a hairsbreadth. (if you feel comfirtable, take it to the car
wash and clean the motor & engine compartment)  i would drain all the oil,
take the plate off the bottom, and look for metal.  put your pinky in the
hole and see if you can find anything in the case,  change the filter.
*Allways be careful of external hoses!!!*  

 a bad connection and losing oil can kill your motor.
- - - 
My 69 bus had the oil light go on yesterday, I was in the middle of a 
crowed city so I pulled off as soon as I could. Checked the engine and 
the hose from the oil cooler to the engine was off, oil was all over the 
engine compartment. I walked to a friends house and called my girlfriend 
she picked me up and we went to the hardware store and got a clamp for 
the hose. We went back to the bus and cut the bad end of the hose off and 
reclamped it. I put in some oil. And I got to work fine. I had put in two 
quarts before and another two quarts at work, but on the way home it 
stalled overheated and I sat around for 5-10 minutes and was underway. It 
did ok but stalled when I slowed down. I had to pop it in gear to save 
the starter and battery. Today it's hard to crank and stalls when I go 
into gear. To oil is a little high although it was fine yesterday, I 
think I'll drain some out. So do I need a rebuild. The engine has about 
8K miles on it and ran fine till yesterday, what kind of damage could I 
have done? Thanks.