Recently we outfitted a Wrangler Unlimited with a Rock Krawler long-arm suspension. The kit came with a really nice bellypan/crossmember that left the transfer case untouchable, but we had a whole bunch of real estate in front of it just waiting to be claimed by a rock. Rock Krawler directed us to Jeep Medic Fabrication's 1/4-inch A-572 steel tranny and engine skid for a 4.0L that was more than stout enough to lay the entire Jeep on. It was heavy, but we got it on in less than 45 minutes including drilling two holes in the bellypan to mount the engine/tranny skid.
Jeep Medic has a variety of engine skids for long- or short-arm Jeeps, both TJ and Unlimited 4.0L Wranglers.
The Jeep Medic engine skid guards not only the 4.0L's engine oil pan, but also the tranny pan. If you use it in conjunction with a bellypan or a long-arm kit from Rubicon Express, Rock Krawler, or Full Traction, you can basically have one long ramp to glide over a rock with. | 
You can use one of two sets of holes to attach the angle iron to the engine skid. We could only use the top two holes on our Jeep. Remember to leave all the bolts loose until the end so you can get everything together. | 
Once we had the front of the engine skid mounted, we drilled some holes for the engine skid to attach to. The engine skid comes with all the supplied hardware and should bolt directly up to the stock transfer-case crossmember, but you might have to drill holes like we did with an aftermarket long-arm belly skid. |
A 9/16 box wrench and socket is all it takes to install the entire engine skid. The first bracket should attach to the motor mounts, with the supplied angle iron attaching the engine skid to the frame-mounted brackets. | | |