1990 Blazer- 700R4, NP241, manual locking hubs.
When I shift the transfer case into 4HI, the indicator light on the dashboard does not come on and it feels no different to drive than it does in 2HI. Previous owner told me that 4LO grinds horribly so I haven't attempted to shift into 4LO. Also, the Blazer came with a spare transfer case in the back. I assume transfer case is toast? Also, with the hubs unlocked and the transfer case in 2HI, I can manually spin the front half of the front driveshaft, the half that connects to the front differential.