How to? Chevy 5 speed Manual NV3500 Disassembly : Tear-down Part 2. Its not that bad.

After I removed the shifter detent plug I was able to remove the spring and pin. Separating both halves of the transmission. Remove the 2 pins in the shifter rail to remove the rail and free the forks. Remove the side retaining bolts for the reverse idler gear. Remove the 3 lateral bolts that hold the gear train retainer plate to the housing.. on the 2wd model youll have to tap the tail shaft with a block of wood and hammer because there is no way to remove the snap ring on the output shaft bearing from the tailshaft housing. After that the entire gear train will fall out. Be careful, many of the caged roller bearing are now loose and any slight movement youll lose em! There are 3 to be aware of! 2 on either side of the cluster gear and one in the mainshaft assembly itself.