Where is this oil leaking from?
 

1994 C280 with 98k miles.

I noticed smoke from under the car after a 30 minute, interstate drive. I looked and oil had dripped on the exhaust. Next day, put it up on ramps and a good bit of oil is all over the side of the transmission housing toward the front of the car and it is dripping down on the exhaust.

So, where is this oil coming from? Oil is on the housing...but no oil is draining down from above (the engine). It isn't running down from there. Oil wouldn't be coming from the tranny housing, and yes it is oil, not transmission fluid.

Is there something in that area that could "squirt" oil out at higher speed or oil pressure?

Where is this coming from?

It's not from leaking valve covers, is it?

It is NOT dripping from above. from under the car, I see the oil that is gathered on the front of the tranny - but can't see where it is coming from including running down from the engine.

Oikl often comes out the front and gets blown back. The drip pan prevents you from seeing where the drips originate. Remove it and drive around for a few days to see where your puddle builds.
If it is coming form the rear, then it could be at the valve cover, head or at the rear main seal.

Yeah, that makes sense. From the top, I see no oil at all (valve cover). I'm thinking it has to be maybe the rear seal. I'll report back. On the other hand, this did start after I got my oil/filter changed now that I think about it so maybe the new filter wasn't put on right or tight enough and that is leaking.

Ok, more info.

1. About 3 months ago, local indy shop replaced the water pump, tensioner, belts, etc. They also did an oil/filter change.
2. This leak started the next day.
3. I have no idea why I didn't connect the two.
4. Oil appears to be on the block on the front right and left corners -- but running and at high revs I don't see it leaking or bubbles or anything -- I don't think this is where the (big) leak is coming from. Not on the sides at all. Not from valve covers.
5. Could it possibly be the oil filter? I can't see it.
6. Someone mentioned the bottom of the oil dipstick tube?

Any help or input is appreciated.

Where's the oil coming from?
 

I'm with Hirnbeiss, leaning toward rear main seal or valve cover. I don't know which side of the block the oil level sending unit is on in your engine, but that's also a place for leaks, and it's down low enough so that it isn't dripping from above.