Just put the 10w30 and the GL-4 in there 50/50 blend. The GL-4 will provide the extreme pressure additives for the transaxle final reduction gearset and the differential the 10W30 will provide a nice carrier oil. It will be a tad thick, but drive it very hard in second and third gear for a bit and that will chop it up. It will take a week for the EP package to clean up the old lubricant. and change the match braking on the blockers and cones. Now get to it or are you just going to post about it for weeks and do nothing?