so lately i have noticed that when i am coming to stop with no throttle being given i get a strange clunking in my drive line sounds like its coming from the rear axle but i cant be sure. I have also noticed that my pinion seal is leaking could my pinion bearing be bad?

 

Check the transmission mount. Mine used to do this because the rubber just ripped apart. Check it real quick by seeing if the driveline, tranny/tcase, can be moved up a ton, or just look at the mount itself. Replace it and you should be good!
As for the pinion seal leaking. Simply just replace the seal, if the bearing was bad then I believe it would squeak when the car was moving as well as the driveshaft would have play in it.