Dexron

Seems silly to have 1/2 new fluid & 1/2 old fluid.....
A simple way to drain the c'ter if it does not have a drain plug. Drill a 1/8" hole, use grease on the drill bit to collect metal. Let it drain. Once fully drained, rotate c'ter slightly so that hole is not at the bottom. Wipe area thoroughly with solvent. Install a pop rivet & smear with silicon to seal it.