I drilled to the bottom of the vein AND NO FURTHER!!! This is the one that can ruin your box. If you go through the vein and all the way into the main cavity of the box, your box is ruined.
I've never drilled a box but it sounds worse than it actually would be to do because once you've drilled into the port you'd still have to drill thru a bunch to get into the main cavity of the box and ruin it. So sounds like drill a little, check, drill, keep checking, just take your time and it wouldnt be a big deal. This is something I want to do eventually.
Fred thanks for the info, how about a closer pic of how your cylinder is mounted to the diff.
