1992 Nissan Truck 1992 Nissan transmission/clutch issue!

Ok I have a 1992 Nissan pickup that I was having transmission problems with! It is a 4cyl manual! The last owner put in a new clutch but said it wouldnt shift right! I bought the truck and did a new slave cylinder, master cylinder and the truck was still hard to get it in! Later down the road it started popping out of 5th then 1st! So this past weekend I purchase a rebuilt 1994 nissan pickup transmission and put it in my 1992. I used the 92 clutch fork and throwout beaing because the 1994 didnt come with one! When I bolted it to the engine I noticed that the driveshaft had a space in it right where the rear tail meets up with the splines. On my 1992 it has a gold cup looking adapter to fill that spot and the 1994 didnt! Everything else looked the same though! I go to start it up and push the clutch in and immediately the clutch felt weird/hard to push in. I got under the truck and it looks like the slave cylinder is doing its job. But when I select the gears and let the clutch out nothing happens! Its like the clutch wont disengage at all! Has this happened to anyone else? Could it be the wrong clutch fork or throwout bearing? Or did the fork just come off of the pivot ball? Also its not the drive shaft because I can turn it manually and it turns the transmission. Could anyone tell me if the 1994 driveshaft is alittle longer than the 92 so I can replace that small gap as well? Thanks for your help!