Does the "new to you" Volvo have an automatic transmission? If it's manual, I've never heard that it needs to be disconnected, but not sure. Automatic? Yes. it requires a 13mm or 1/2 inch wrench to remove the four nuts. at the rear universal joint, just in front of the differential. Piece of cake. Just make certain that the fact that the car is in gear, isn't the only thing keeping it from rolling; once the nut is removed, securing the driveshaft to the differential, the fact that it is in gear, will have no effect on whether it rolls or not. (Set the e-brake and block the wheels before disconnecting the driveshaft, to make a long story short.)

Jerry