If you're following the instructions posted (getting it up to the proper temp., cycling it through the gears, being on level ground, etc), & opening the correct plug (upper fill/check plug), then anything coming out is overfill, & shouldn't be in there anyway.
Look at what is said in the posted instructions (right below where it says "DO NOT OVERFILL") about too much fluid in the system...
If you don't have a thermometer (cheap @ Harbor Freight) lay your hand on the bottom of the pan, it should be warm to the touch, (a bit above body temp) not cool, & not so hot that you can't leave your hand on it.