Rear end spitting out gear oil??

Anyone ever had their rear end spit out gear oil through the breather?? At first I just put a little K&N filter on the side of the hogs head. After I noticed it spitting out oil, I put the factory vent hose back on and routed it so the end was higher than the rearend. Still spits out oil though. Only seems to do it when I'm at highway speeds, driving through town doesn't seem to produce much, if any. Oh and another thing---is there some kind of sensor in the rear end for the brake system?? The brake light came on and stayed on since. Checked the fluid levels and it is ok. Buddy told me to loosen the E-brake cable and and re tighten it because of some sensor in the rear end. I did this the last time it came on and it worked-- light cut off, but didn't work this time. Anyone have any ideas??

what kind of truck? more details please

yeah, we need the specs

Oh yeah sorry 'bout that. I own a '92 Chevy 3500 Ext. cab dually.

sounds like your rearend is overheating, a bad bearing or ring and pinion. is there and signs of heat like the paint on the rear cover looks baked or maybe a smell of burnt oil after a trip?

Nope none of that. Actually, I just drove it 26 hrs round trip to Arkansas and back to Virginia. Made no noise and smells just fine. Like I said it just spits out enough to be annoying and leave oil spots all over the tailgate, plus coat everything underneath that is on the side of and behind the breather hose with a light film--especially annoying when you have to work on something on that side of the truck. Would pinion angle have anything to do with it?? Because we changed the pinion angle when bagged the truck so that the drive shaft would line up through all the range of motion. I'm thinking maybe it was a little over filled or maybe because the rear is tilted slightly more forward to correct the pinion angle that the oil runs toward the breather tube or a combo of both????

maybe overfilled, it will find the level it wants to be at soon!!

that is a possiblity