Ariel Winter's sister -- and current guardian -- sat down for a deposition with her mother's attorneys, and was hammered with questions about drug use ... TMZ has learned ... but the questions for the most part netted the history of your average Joan.
Shanelle Gray was grilled last week by Chrystal Workman's attorneys in the ongoing guardianship case for the "Modern Family" star -- and sources connected to Shanelle tell us she was asked if she ever took drugs ... specifically, cocaine.
We're told Shanelle said she tried cocaine only once -- either in 2005 or 2006 -- at a Hollywood party. She thought someone laced it with something bad ... because she got sick.
We're told Shanelle told the attorneys she went to the hospital as a precautionary measure, and was released that same night.
We're also told Shanelle copped to spending a "few days in jail" in Virgina, when she was 19 ... in connection with a reckless driving incident.
And our sources say Shanelle was asked if she ever got a DUI. We're told she said she was pulled over in LA in 2005 or 2006 and was given a ticket on a night when she had "one glass of wine." She says the judge eventually threw out the ticket because her blood alcohol level was so low.
Sources close to Chrystal tell us her attorneys plan to use Shanelle's depo info during the guardianship hearing ... in an attempt to show she is not a suitable role model or guardian for Ariel.