One of Residential Capital LLC's largest unsecured creditors is seeking court approval to sue the mortgage firm's parent, Ally Financial Inc., increasing pressure on the government-owned auto lender to pay more money, Dow Jones Newswires reported yesterday. Wilmington Trust, a trustee for $1 billion of ResCap senior unsecured bonds, renewed arguments on Friday that Ally stripped ResCap of valuable assets prior to the mortgage subsidiary's chapter 11 filing last May, assets that Wilmington says are worth billions of dollars. A key transaction at issue is the transfer of ResCap's ownership stake in Ally Bank, the depository subsidiary of Ally Financial that Wilmington and other creditors claim was ResCap's most valuable asset. Ally completed that transaction in 2009, a move Wilmington says exacerbated ResCap's financial problems as it faced rising litigation over soured residential mortgage-backed securities.