your disconect is fine. something is up in the differential. yes your driver side driveshaft is always connected but when in 2wd, your spider gears should spin letting you freely turn your driveshaft. likewise you can turn your both wheels independent of each other and of the driveshaft. if you have a limited slip or places a locker in the front, this will cause you driverside wheel to always spin the driveshaft due to no spiders. If you dont have a limited slip or a locker, then there may be something wrong with your spiders in the front carrier. try to spin the driveshaft while all wheels are on the ground. if it doesn't turn either directions then pull the cover, drain the fluid and check the spiders. make sure they didnt get jammed. if it does spin, than you are ok. it may take some force. dont worry about the spining driveshaft when you are driving if it checks out ok...there is no load on it.
Its not what you buy...its what you BUILD!!!
1995 YJ ,SOA with 4" procomp front 3.5" BDS rear 1" shackle rear, custom stearing, 35x12.50x15 pro-comp MTs, warn xd9000i, on-board air from A/C, dana 44 rear and 30 front with 4.56, powertrax no-spin rear, custom disks rear/trutrac front, warn front shafts, HD SYE kit, HD front and rear driveshafts, Warn 4X flairs, PIAA 520 ligts and on and on and on :)