? clutch release on 94 Z24 3.1L 5 speed

I recently purchased this '94 Z24 - 5 spd with 100,000. Previous owner replaced clutch master cylinder 10 K ago. All shifting was fine. Now after driving 1,000 with the last up a gravel driveway, it is virtually impossible to shift between gears. Reverse is a terrible grinding. Can shift between 3rd and 4 th a little with brute strength.
The clutch does not seem to be releasing. Only a little touch of pressure in the last inch of travel at bottom.
Any ideas?
Slave cylinder part listing said that transmission must be removed for replacement on 5-spd. Is this true???

During this same time the cruise control went to only intermittent functioning.