Not sure what you mean by manually shifting it? If you mean manually going from 1-2 I can do that. Although it's hard to manually put it into 1 as the linkage needs to be adjusted some.
And I don't know the stall. The engine and torque converter are out of a motor home. I'm not sure what the tranny is out of but I know it's not the motor home tranny because that was swapped out due to the tailshaft.