The rear would grind all the time if it was grinding. The grinding when you shift would be your transmission I hate to say but like you said at the power your at she has been a good one. The Clunk could be alot of different things since the driveshaft is brand new it for sure needs to be checked out but not all of them are not drivetrain releated could also be an issue with your suspension (I had a popping in my rear one time that end up being the Lower Control arm )or your exhaust hitting but there is only one way to find out what it is. The leak its hopefully the vent from a little to much fluid during install if not it would be easy to find either way. There is only one way to found out whats the issue is.
Was this the only thing you had installed at the time?
Last edited by JLE58; 06-05-2013 at 02:28 PM.