While installing a chain box I drilled two holes in the side and tapped them 3/8-16. I thought I would be drilling into nothing, but the drill hit something. What is behind this area?
On skid steers, it is the chain case with the drive chains from the hyd. motor in the middle to each wheel hub. Usually there is a few inches of oil in the bottom for the chains to pick up lube. With your ctl with 1 drive motor in the back, I would have guessed that you would be fine dirlling/tapping also. If everything still works and no fluids are leaking or disapearing, run it. Check with your dealer to be sure, I've had Case, NH, JD & Gehl SS's but never a BC. Or ask at Skid Steers
If no problem by now you should be OK. That controller box is about 1 &1/4" thick with circuit board mounted to inward side, and back of it is filled with epoxy to seal it. My have just bumped up against the back side of it.