I put the jack under the bell housing. I don't guess it really matters, as long as you support it. If you don't, you'll experience a surprise. You'll likely have a surprise anyway when you try to remove those 6 frame bolts.
Dodge did not build my Jeep.
1988 Wrangler,4.2L I-6, Howell EFI JP-1,CRT HEI Ign,AX15 ext slave conversion, Zone 2.5" lift + 1/2" booms, BFG 31 x 10.5, Bestop.