I am looking at a 2004 chevy trailblazer from auction that has black specks in...

[chuck]

...the tranny oil. Oil is tan.? It has a light smell. Works fine when driving. Specks are thin and as large as 1/16th of an inch. Whats the issue?

[edcoba]

it sounds like residue buildup formed on the interior of the pan that peels off and will ultimately mix with the fluid. buildup is usually caused from the heat generated from the transmission.
I had a similar situation with my 02 GMC company truck and that's what I was told. I did a flush and filter/fluid change and was fine.