10 bolt rear diff fluid amount

For those of you with 1/2 tons that have changed rear diff lube, how much does it take? ('99 4x4 silvy--it is a ten bolt--cause my last 1/2 ton had a 14 bolt--this is a ten bolt). I only ask cause my fill plug stripped out and I had to fill from the vent tube. And the only way to tell if you have put in enough is through the fill plug. So I put in 2.5 quarts. Not real worried about overfilling, cause of the vent, but do not want to under fill. Done many 10 bolts, but my memory stinks, my last 3/4 ton took 4 quarts, so I guessed! Thaks for any help!

Well it should say in your owner's manual I would think. If not check out the car/truck specific forum you are refering to, as most people generally don't check in here that often.

opps!