Truck will not go into gear

I have replaced all clutch parts. Even the guide barring that the transmission shaft sits on. Still nothing. It will shift without using the clutch and was driven like that for a year.

It might be worth having a professional mechanic look at it before you destroy a very expensive transmission…

How are you getting started in 1st gear? If you are putting it in gear, hitting the starter and then taking off when the motor starts you are going to kill the starter as well as the transmission.

IF you did a proper job of replacing the clutch, throw out bearing, pilot bearing, and pressure plate, and you had a good surface on the fly wheel when you did this, then I have to ask, did you check the master and slave clutch cylinders for leaks and proper operation?
is there a leak in the actuator line? Have you bled the line?
If no, do that. If yes, then you may have bad syncromesh in your gears, and the easy way to fix that is go to the recycle yard, and buy a replacement transmission. the expensive way is to take it the transmission shop and hock the family jewels to pay for repairs or replacement with new parts or new transmission.

master and slave replaced and bled. surface on flywheel was good. yes he was bumping it in first until it went.
when he got it going he was able to shift without clutch.

Remove the slave cylinder from the transmission without disconnectiong the hydraulic line and wire tie it to something. Now drive the vehicle and if it can still be shifted without the clutch hydraulics there’s something wrong in the clutch assembly. Are you sure the clutch disk was installed correctly?

Tester