I believe the easiest way to check if your torque tube seal is leaking would be to check the differential fluid level. If it's not over full then your torque tube seal is ok. If your trans fluid is low and rear end high then fluid is moving past the torque tube seal and it needs fixing. If you are seeing fluid coming out at the brake drum your axle seals are shot and need fixing, a much easier task than replacing the torque tube seal. I believe consensus is Okie seal is best way to go if you need it.
