Drivetrain issue

Driving on level ground turning slightly left I heard a clicking and then had no drive at all. Front drive shaft was spinning but could not move. Towed it home and started testing. It will move if I lock in the differential, but nothing in normal high or low range. suspect the left front cv as it has been clicking for a week or so. If you loose drive to one wheel on this awd system, do you loose all drive when differential is not locked. Hoping its just something in front axle assembly. Hate to think it could be in trans or transfer case.
This is on a 1995 Discovery with just under 100,000 miles.

If the front driveshaft is turning that would point to something in the front diff going south. The centers (main gear set up) for these cover many years and are fairly inexpensive in a used state. These are like in Ford diffs and the center section drops out after the axles are removed. getting a good used one saves you the trouble of setting up the gear set.

'95 R.R.C. Lwb
'76 Series III Hybrid 109
'70 Rover 3500S

CV joints are known to explode too...

Absolutely... So, an exploratory surgery is in the offing, either way. If you find blown CV joints when you remove them it might still be a good idea to check the diff for damage, and clean out all the old diff grease and put in new synthetic as a safety precaution (and good maintainence).

'95 R.R.C. Lwb
'76 Series III Hybrid 109
'70 Rover 3500S

Kelmf, where are you located? Have you diagnosed yet?