What could be the problem?

[el40]

Truck is a 1998 GMC K1500 5.7 5 speed nv3500

After a transmission rebuilt, new clutch , new pressure plate, new slave and master cylinder, new pilot bearing , new flywheel
The truck still grinds from 3 to 2 gear and the reverse will not Go in and 1sr gear is very hard and I have try a few times , it just grind a lot: the clutch pedal also feels flimsy.

when truck is off the shifter goes into all gears fine

what is the problem here

 

[F4U-1A]

Your clutch pedal should be hard as F to engage. Like mine from the factory new. Could have air in the hydraulic system?

 

[Schurkey]

Faulty clutch hydraulics

WORN-OUT CLUTCH DISC

Warped or contaminated clutch disc

In all cases where the transmission shifts fine with the engine off, but grinds when the engine runs--the clutch is not/can not release fully.