You have an axle seal leaking, I will show you a rendering of how the seal attaches to the axle. in a second,
as to the fluid coming out the vent tube, you are spinning the gears faster, and this can cause it a little. if this is all it is just extend the tube some. or if it was setup too tight the fluid can overheat and cause this also, or water in the fluid also, if the fluid smells burnt or looks bad it may be overheating, if it is milky after driving it has water in it.
Unless the housing is scarred or cracked the seal is the leak. This is common.
the don't go above the battery.
Hey, I just realized you said the tubes are leaking at the center section.
The housing may be warped, You could try cleaning it and running some sealer around the tubes, then paintng it. and see if that stops the leak.