UGH! What size is this fitting!!

[eclipse]

Ok so I swapped the 10bolt front in my 85 K10 for one with 4.10s, got it all in, the only thing I need is the fitting that goes on top of the diff for the vent tube. The one on my old 10bolt is broke and won't come out. I dont know what size or where to get that damn little fitting. Its the last thing I have left tell I can sell the truck

 

[goldwing2000]

It's not a threaded fitting. It's pressed in. I drilled out the pressed-in deal and threaded the hole for 1/4" NPT then installed a 45° brass elbow.

 

[AZ79K5Project]

It's not a threaded fitting. It's pressed in. I drilled out the pressed-in deal and threaded the hole for 1/4" NPT then installed a 45° brass elbow.

Just tapped mine when it fell out. Be careful with shavings falling into axle tubes. Metal shavings, gears and bearings don't mix well.