E30 Diff question

[EvoSW@xxxxxxx]

Hi, i have a question for my 85' 325e, i think it is my diff but i would like 
another opinion. The problem is when i accelerate there is a loud clunking 
that you can hear as well as feel coming from the rear of the car, the rate 
of the clunking increases with speed but stops at about 7mph, and then 
everything is fine. The clunking is worse the harder i accelerate. Any ideas? 
Thanks

- -Matt Johnston

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