GM Transmission Oil Cooler Line Disconnect Tool Specially designed to work in tight places, and so simple to operate you can do it with just one hand.. After inserting into the quick-connect fitting, a quarter turn of the tool quickly and easily releases the fitting on the transmission end of the transmission-to-radiator oil cooler line. Works on 2WD and 4WD pickups and vans with electronic shift overdrive automatic transmission: 1991-current 4L80E transmissions; 1993-current 4L60E transmissions 7937