No Engine Braking In Manual 1st Gear

Improperly torqued valve body bolts (gasket damaged), check balls missing or damaged, valve body components (3-4 shift valve, low reverse clutch modulator valve, D2 valve, 4-3-2 timing valve, 2-3 shift valve, coast clutch shift valve), valve body separator plate, coast clutch assembly and low reverse clutch assembly.