So me & a 20% coupon went to Harbor Freight, and bought their trans jack. Its actually pretty nice.
Dropped & split the tcase.
It appears the problem is a badly stretched chain. Playing with it on the cart, it appears the chain is so sloppy it falls behind the shift lever that engages the fork for the 4wd engagement, and sometimes prevents it from going in. Explains why it felt like it was in 2-Low the other day. Got a new chain on order, but it wont be here til friday. I went thru the whole case last year, so it doesnt need anything else. Shouldve just done the chain then.
Got the trans dropped too:
Trans jack made it super easy. Got the rear main seal replaced, and the trans is already back up in the truck. Sucks installing an E4OD by yourself. Just waiting on the tcase chain now, to finish reassembly.