So I was changing the oil today and while under the truck thought I should look over the undercariage. It could use a good washing but no problems. Then I go to the rear and see oil on the rightside of the axle. Where is oil coming from? I find it pretty quickly. The Expo diff cover has a breather hole that I had plugged but now was open. I guess the pressure blew it out. So I made a plug and JB Weld it in the hole, let's see that blow out. Checked the fluid level and it was down a little but not bad. Topped it off and closed it up. Just glad I found it before it drained the pumpkin.