Bad CV?
 

Yesterday I did an oil change on my 09 C70. As soon as I dropped the plastic underside protector, I noticed heavy black grease on the drivers side around the area of the inner CV boot. I checked the boot but there were no cracks or tears. I examined it closer and it looked like the grease was coming out of the large end of the inner boot where it attaches to the transmission. The clamp was tight. There wasn't a whole lot of grease spewed around though. Maybe 1/8 - 1/4 cup total. What does this mean? Can I drive it? Do I need a new boot and clamp? If so, can I DIY? I'm not afraid of DIY stuff. I've replaced the timing belt, rear lower and upper control arms, front lower control arms, spark plugs, A/C pump, etc. My main concern is if I can drive it and possibly sell it this way.

the CV boot keeps grease in, dirt out. If its leaking grease, eventually the joint will go dry so the thing to do is to replace the boot and regrease the joint. Most boot kits come with a foil pack of grease - check Volvo friendly web stores for a kit to match your axle.