Why will a 1989 Nissan Pickup Truck not take the gears after replacing the clutch?

If a 1989 Nissan Pickup Truck is not engaging gears after a clutch replacement, it could be due to incorrect installation of the clutch components, such as misalignment of the clutch disc or pressure plate. Additionally, issues with the hydraulic system, such as low fluid levels or air in the lines, can prevent proper clutch operation. It's also possible that the clutch master or slave cylinder is faulty. Finally, ensure that the transmission linkage is correctly adjusted and functioning.