I would be willing to bet you have a bad passenger side cv shaft. My car did the exact same thing, like 2 metal pieces covered in rubber hitting each other. The right rear axle is the one that gets the majority of the power put to it. They are usually the first to go. I run a salvage yard so I took a used and in good condition drivers side cv shaft from a 240 and put it on the passenger side of my car. It fixed the problem. You have a bad cv shaft. The joints inside the housing spin inside of a hardened metal body. When the boot tears, the oil leaks out and it is virtually the same principle as running your engine with no oil. It tears them up, creates "slop" because of the worn metal. That is the clunking noise you are hearing.

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2005 Accord Hybrid (Wifes)
1995 Subaru Impreza L AWD (Snow car)
1984 GMC Sierra 1500 (Mine)
1983 300CD Best $ I ever spent. (Mine)
1984 190D (sold and glad I did)
1983 300D (sold and wished I hadn't)