filling the front diff

ok, i have a winch and plow setup on my 500ho, filling the front diff is a real pain. i have to take off the plow mount and unbolt the winch to get to the fill plug. well today i pulled the diff to replace the seals and saw that the vent on the top has a clear tube going up under the pod light. now i fill it with the same size hose and use a brake bleeder to pump it in. why not just use the vent tube. its ease to get to, i know how much to put in it. any thoughts on why not to use it?

filling the front diff

ok, i have a winch and plow setup on my 500ho, filling the front diff is a real pain. i have to take off the plow mount and unbolt the winch to get to the fill plug. well today i pulled the diff to replace the seals and saw that the vent on the top has a clear tube going up under the pod light. now i fill it with the same size hose and use a brake bleeder to pump it in. why not just use the vent tube. its ease to get to, i know how much to put in it. any thoughts on why not to use it?