Hi Fordnatics. Funny thing hapened today while draining my diff oil to put in a new cover gasget. First step drain oil. Next undo bottom middle bolt to drain out oil. No oil? Empty? Use pick to check for blockeges. No blockage. The bolt hole is a blind hole? I removed the cover and the oil poured out. Cleaned up the diff and checked if an intersecting hole may have been drilled to drain the oil out but it was blocked! No other hole. I wiped the inside are of the diff above the bolt ans scratched around to find where the oil would be let out but nothing. Do any of the XA XB XC Borgwarner diffs not have drain holes?