t-case shift question

todat I attempted to sort out my 4wd to low range shift problem. I adjusted the linkage as per Hayne's book and yes I got my low range back.
BUT: As I had both axles off the ground on one side to check 4wd, I noticed that 4wd low drives both axles but 4wd hi only turns the rear!
Whats up? I dont if this was pre existing or not.
This is a bone stock 86 xj 2.8 with the 904 trans and np228 t-case.

Faulty or slow vac connect on the front axle?

ya forgot about disco axle

I am checking on the front axle disco in the morning and yes I had high range adjusted right.
But after some more research I find that the np228 has an open differential in it. It only locks up in 4low.
Theoretically on the 228 in 4HI you can spin just one wheel since there is an open diff in the tcase. Think of a one legged diff versus a diff with a locker and you get the picture. Heres where I got the info. http://www.bigscaryjeep.com/BSJ.html Look for the 228 refefence near the bottom. Yeah the 228 is from a FSJ origonally it was used behing AMC 360 and 401 V8s.
I'm thinking this is whats going on becouse when the case goes from 4LO to 4HI the fron driveshaft jerks like something ingages. I'm gonna block the rear wheels in the morning and see if I can get the front to drive in 4HI.
Keep you posted.