An easy method to use the pump for those where the supplied fitting will not screw into the lower unit. Find one of those little plastic tips that either screws on or snaps over a tube of silicone glue or glue bottles, cut just enough off the tip to get it into the threaded fill hole, stuff the end of the pump fitting in the larger end, presto, one size fits all. Drain the lower oil, replace the screw loosely, pump til the oil comes out the top screw, tighten the top screw, remove and quickly replace the lower screw.