Yes, the steel/cork/steel sandwich is correct. If the cork seal isn't seriously worn or damaged, all you probably need to do is tighten the gland nut firmly. All the motion between the torque tube and pivot ball does is slides in and out less than an inch as the rear axle moves up and down. There's no rotation at all. Getting the ring nut tight usually stops any leakage. Replacing that seal requires lowering the torque tube after unbolting the universal joint and removing the pivot ball, and there's a danger of the tube slamming down under the vehicle's weight unless the frame, (NOT the rear axle) is supported by jack stands. Fabricating a new seal with square neoprene O ring material can be done by wrapping a piece of the O ring material around the tube, cutting it at a 45 degree angle, and using super glue to join the ends. That material will outlive the original cork material, and the fix doesn't require lowering the torque tube. Send me a private message if you like, and I'll respond with a phone number. It's always easier to describe a fix such as this in a 2-way voice conversation.
Jerry
