One part of Ground-Up that we were never really very happy with was the T-case crossmember. The design was sound, but the aluminum T-case was hanging out where a big rock could easily grab it. A broken NV231J housing in the middle of the Rubicon would be a big problem. To remedy this we added another length of 13⁄4-inch, 0.120-wall DOM bent to match the first, along with a couple of sleeves and bushings, and four tabs. Then 3⁄16-inch skidplate was added to close up the vulnerable areas.