You can remove the oil using a syringe with a small 1/8" hose slipped on the end. Auto parts sell these. I use about a 5" of hose. Keep slurping and poking the hose to the low point until no oil remains. Refill the correct amount. I found the level is about 3/8" below the edge of the fill hole when full. Filling to the hole will result in oil being forced out past the bolts and collecting in depressions in the gear cover.
Roy