I had the same problem with the muffler or resinator (the one closest to the engine) contacting the driveshaft. The first step is to get some new heavy duty rubber exhaust donuts. Your old donuts may be missing or deteriorated. Also there is a muffler support near the transmission if I remember correctly. See if these can be adjusted to eliminate contact. If that doesn't work here's my crude and nasty fix, I wired it out of the way. I got a stainless steel rigging turnbuckle at a ship chandler for about $8.00. Then I got some stainless steel wire. Use stainless because you only want to McGyver this thing together once. Use a turnbuckle because you can tighten it at a later date if it sags further and you need more clearance.

There is a metal support flange on the rear of the muffler (at least there was on mine) and there is a hole on the left underside of the car. Run the wire two or three times between the flange and the hole. Have a friend stretch his legs under the passenger side until they contact the muffler. Have him push gently on the exhaust system and hold it while you take up the slack on the wire. Put the turnbuckle in place and slowly tighten. You don't need much to get the desired clearance. Be careful when pushing around an exhaust system you could break a component and they are expensive.
Good luck