Just researching this problem I found today and decided to chime in. Wondering if this problem is more common. I purchased GMC Sierra x31 a couple of weeks ago. Compared to my father in laws trail boss it seems identical. I was doing a break in oil change at 500 miles and found this on passenger side. Took it to the dealer and they immediately said they will replace the entire axle next week. I can’t see the hole but they are convinced. Could be a one off defect but I don’t seem to be the only one. Truck is new so it’s never left the pavement or even driven hard yet. Truck totally stock.
Curious to say the least.
