front of transfer box front output flange bolts directly to it,your vehicle is equal 4 wheel drive with same torque going to both axles viscous ensures both axles get the same torque,while allowing some rotation so that you dont get wind up in transmission while cornering,you check it isnt seized solid as can happen by jacking one wheel up preferably front so you can leave hand brake on and turning with large bar on wheel nut ,it should turn slowly stiffly and smoothly if wheel is locked replace viscous unit ,can be done with transfer box still in vehicle