Put a jack stand under the oil pan as well as under the output shaft cone on the t-case. You don't want the whole weight of the trans/t-case sitting on that output shaft, its only aluminum.
Unbolt the trans mount first, and then the 6 bolts on the skid. Put a floor jack under the skid before the last bolts come out cause it weighs about 75lbs.
'87 YJ, 4.2L built and bored, 8.5" of lift, 8.8 rear, AX15/NP 231, Tom Woods drive shafts, Flat fenders, 12,000LB winch, Custom bumpers, Rattle can paint job. Never completed...