if it is too bad to drive with it in -
pull it out! get it out of there before you distroy more stuff (pinion bearing / t-case bearing)
i had this issue as well - though in mine i blew the DC ball - probably from underlubrications and terrible vibes from bad pinion angle.
id sugest taking it to your local driveshaft shop, and having them look at the DC ball and setup - and get a quote on a rebuild, balance and paint.
if the joint is good - should cost about 80$ for parts and probably 50 for labor so 130 to rebuild it pro.
if they pull it apart, and quote you the $$$ for it and you dont want to pay and the joint is good, take it home, put new u-joints in it, then get it balanced (balancing shouldnt cost too much - $20 maybe?)
U-jouints go for sometihng like $25 a piece so $75 in parts... saves you like$30....
NOw - if the joint is bad (like in my case)
the junkyard $50 shaft
www.car-part.com and put new u-joints in it, or
do like i did and get a shaft from RE - they made it custom for my aplication and it cost $275 for a BRAND new shaft with all new components...
the local driveshaft shop wanted 360 for a new shaft...
here is my write up on pinion angle and DS relationships as well as DS install / removal...
http://www.opiebennett.com/upperdrrveshaft.htm