I checked mine the other day. The rear U joint is somwwhat loose where it connects to the tranny. A replacement has been ordered (I'm going off warrantee within 30 days).
Although I don't know/think it would really be an issue over the long haul, I did apply pressure to the shaft and there was "noise" so I guess it doesn't hurt to replace.
BTW, has anyone replaced this themselves? If so, what did you do to get the driveshaft off?
Brian