BIG,
I would pull the driveshaft and inspect the seal,also inspect the driveshaft input shaft itself, is the input shaft worn/degraded/nicked up in any way?... Ive had one get a nick in it from layin round the shop and my BOYS!
if ya drippin fluid, is it possible ya nicked the seal when ya installed the driveshaft or the input shaft on the driveshaft is buggered up a bit?
I usually get more probs from the speedometer housing leaking than the tailshaft with a good seal and input shaft.
Just tossin out ideas
Tim