If you can get the rear bell slid back far enough to unbolt the u-joint from the intermediate shaft, it might not be necessary to drop the rear axle. Once that's done, the torque tube and driveshaft assembly can probably be unbolted from the crossmember. The "pin" you're refering to might be through the rear shaft, securing it to the universal joint yoke. I'm not sure it's there, but look closely for it once the bell slides back far enough to expose the u-joint fully.
Jerry
