If the input shaft is stuck tightly in the pilot bushing then the tranny input shaft will be energized when the engine is running. In this scenario, the tranny will shift just fine into all gears IF THE ENGINE IS OFF. With the engine running, the clutch disc will properly disengage from the flywheel but the energized shaft keeps the tranny gears moving. The truck will take lurch if the engine is started with the tranny in gear. If the engine is started with the tranny in neutral, then it won’t lurch but you won’t be able to shift into any gear with the engine running.
He doesn't state if it's a Chev or GMC. The Chev's used a bushing, the GMC's used a bearing.
