Rear Cover oil leak

Hey all. I have a 99 silverado z71 4x4 with 155,000 miles on it. 5.3L vortec (iron/steel and not an aluminum block) I have a small oil leak from the rear of the motor drivers side. I notice the leak more right after I change the oil. I changed it myself and used an ac delco oil filter. I can assure this leak is not residual from the oil change. I have replaced the oil pan gasket. (which was leaking) and replaced the oil cooler cap and crush washer that is located just above the oil filter. 2-3 days after my oil change I can see clean oil (just to the point of dripping after 2-3 days) on the 2 tranny bolts, and the two drivers side rear oil pan bolts (one in front of and behind the oil filter). I have cleaned the outside of the motor and added dye to the oil, and I see the dye inside the tranny housing but not really dripping from the rear main seal. I cannot see any dye on the top rear or feel any oil anywhere from the top rear of the motor. So that can rule out valve cover gaskets. I have recently changed out my intake 6 months ago and I do not believe I have left anything loose. The only other place it can be coming from looks like the rear cover. I can do most repairs, but removing and reinstalling a tranny and a transfer case with a floor jack is probably out of my league. What would be a good price and how many hours is fair for this job? I would have them replace the rear main also, while there are there.

Is there anything I am missing???

Hey all. I have a 99 silverado z71 4x4 with 155,000 miles on it. 5.3L vortec (iron/steel and not an aluminum block) I have a small oil leak from the rear of the motor drivers side. I notice the leak more right after I change the oil. I changed it myself and used an ac delco oil filter. I can assure this leak is not residual from the oil change. I have replaced the oil pan gasket. (which was leaking) and replaced the oil cooler cap and crush washer that is located just above the oil filter. 2-3 days after my oil change I can see clean oil (just to the point of dripping after 2-3 days) on the 2 tranny bolts, and the two drivers side rear oil pan bolts (one in front of and behind the oil filter). I have cleaned the outside of the motor and added dye to the oil, and I see the dye inside the tranny housing but not really dripping from the rear main seal. I cannot see any dye on the top rear or feel any oil anywhere from the top rear of the motor. So that can rule out valve cover gaskets. I have recently changed out my intake 6 months ago and I do not believe I have left anything loose. The only other place it can be coming from looks like the rear cover. I can do most repairs, but removing and reinstalling a tranny and a transfer case with a floor jack is probably out of my league. What would be a good price and how many hours is fair for this job? I would have them replace the rear main also, while there are there.

Is there anything I am missing???

with your mileage a wet spot in this area is normal wear and tear...if you leave spots on the ground 3inches in diameter then I would get on with a fix...its leaking so little you can't find the exact location..