Front diff vent leaking fluid

[Orange_F150]

My stock front diff had 150k+ miles and was starting to make noise so I had it replaced with a used unit that had 35k on it.It is a 4:10 ratio.Installed brand new axle shafts since we were in there.Now the mechanic filled the front diff right up to the bottom of the fill hole,(about 1.5 qrts).Everything was fine, drives great, but now fluid is leaking from the front diff vent in the drivers side wheel well.Looks like it was coming out pretty good cause it left a few 3-4" circle puddles in my drive way.Why is it leaking????Any ideas?The filled it with 75/140 Royal Purple.

 

[rwenzing]

There was a TSB for this in 2000 or thereabouts. The factory fix was a revised diff cover and tube but it cost $300 or something ridiculous like that. You can fix it yourself for next to nothing by extending the vent hose up to near the ABS pump/module. That's the stock location for the Ranger FX4 that uses the same front diff as your Trac.