Mine made the same noise. Several bad bearings in the trans and ended up junking the trans from metal chunks flying around. Take it apart and inspect it immediately.
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Not to revive an old thread, but did you ever figure this issue out? I have the exact same problem, wondering if you ever figured it out.
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https://www.svtperformance.com/threads/t56-bearing-whirling-noise-help-me-figure-this-out.1100840/