I replaced my valve cover gaskets about a month ago on my 2.8. It's still leaking on the rear passenger side, can I take off valve cover and re-set it with sealant on the corners and tighten up or should I get a new gasket and redo it over again.

 

I would buy a new VC Gasket and do it again

 

check/replace your cam caps. if the gasket is new, i reuse

 

Are you sure oil is leaking from the gaskets you replaced? I guess I should ask: Did you do the full valve gasket replacement? As in, did you do the cam chain tensioner gaskets and shaft valley seals? Or just the valve gaskets?

Here's a video of the WHOLE thing:Blauparts How To Replace A Leaking Audi Valve Cover Gasket - Replacement Overview - YouTube

and here's a video of just the valve gaskets: Valve Cover Gasket, CamShaft Seal and Cap Replacement VW 2.8L - YouTube

As you can see, they got way more in depth in the first one.

 

I did the vc gaskets and the hockey puck plug things on the back of the block. It seems to be leaking from the lower rear corner on passenger side towards the back of engine. The rear plug is dry when i got my hands behind there and was oil on lower corner of vc.

 

cam caps for the win

 

On the 2.8 there is a cam adjuster on the back of the passenger side bank. If you didn't do cam adjuster gaskets I'd bet that's your problem.