Hello,

The bearing itself should last about 6 to 7 years and maybe more if you don't drive long distances. Usually its the rubber support that fails first than the bearing. The bearing is located within the rubber support (doughnut shaped) and the entire assembly is bolted underneath the car.

The bearing is a sealed type. You can't grease the bearing. Its must be replaced if its noisy or failed. You can grease the U joints if they have greasing nipples. But I doubt they have these as greasing nipples do add weight causing the spinning driveshaft out of balance. The original U joints that came with the car didn't have greasing nipples.

The U joints usually last longer about 10 years or more. Its the last two rearward U joints that usually need replacement as they flex more often. A special care is needed to replace the U joints. Some mechanics clamp the driveshaft with vice-grips in order to remove difficult U joint. If incorrectly done the driveshaft may bent and went out of balance. It happened to me and I had to replace the entire driveshaft. The symptom was rumbling sounds after you've reached certain speeds - about 50kmh. Above that speed it just disappears.

To answer your questions:
1) There's suppose to be very little play (less than 2-3mm) in any direction
2) see above explanation
3) An out of balance driveshaft, non-OEM quality bearing or rubber support

From your descriptions it looks like the rubber 'doughnut' supporting the bearing has failed. Be sure to replace this with original parts for longevity.

Hope this helps.

Amarin.