I was under the car and saw a perfect ring of grease around the transmission tunnel, definitely coming from the driveshaft spinning and flinging grease.


It's location is right where the drive shaft is connected to the transmission (iirc), not sure it's the transmission but it's connected to something over there.

What can this be?

 

CV grease. It's either the boot has torn, or the grease has thinned out and is pushing its way out of the strap.

 

Pics would be helpful here.