I have pulled the pan on the Avalanche with 20miles on it.
Had junk in the bottom.
Pulled one from an 03 100k had all kinds on sludge and junk in the bottom.

Tapping while in the vehilce has been done for decades.
You will not get all the trash out when done on the vehicle.
But I believe it won't matter.
Get all you can use lots of grease reach inside with grease on finger.
Clean well and done.

From what I seem in this 03.
The pick up suction must not be on the bottom of the pan.

Now on the removal.
2wd take a couple of hours. To remove drill and tap and return.
4wd. Gin a be there all day.

 

Aww come on your making it sound like its that hard to pull a pan. Ive done several and the only diff between 2wd and 4x4 is unbolt the axles from the front diff set em aside undo the diff bolts and just drop it enough to get the pan out. You dont even have to disconnect the front driveshaft. Then again ive done several but for oil pan gaskets so its really the same. If its 2wd nnbs you have to drop the steering rack but that takes minutes.

 

tapping while on the vehicle is just asking for issues, for sure not the correct way to do it

 

so is putting a turbo on your truck, your asking for issues! lol

 

sure, but completely different scenario. Drilling metal shavings in the oil pan and just hoping that draining the oil or sticking your finger in the hole with some grease to get them out. Yea that seems like the proper way to do things

 

My return is in the oil level sensor spot. It was there when I bought the truck. If I was to do it again, I would tap the timing cover. IMO easier to get off that the oil pan.

 

I agree. A few hours of work to avoid metal shavings in the pan is worth the trouble. I'm betting most probably need a new oil pan gasket in the first place lol.