Definitely replace the rubber coupling. Also check the bolts and the retainer nuts. (they should be replaced anyway as they are designed for a one time torque down.) If the bolts aren't damaged, they can probably be reused. On some models, there is an alignment pin in the center of the output flange which mates with the driveshaft. There is a bushing or bearing in the center of the driveshaft that this pin mates with. You should probably replace that as well. Check the alignment pin for excessive wear also. I believe that model has a two piece driveshaft, so if you are comfortable working on it go ahead, otherwise, give it to a pro.