I have suffered both problems, leaking axle seal and torque tube seal. The easiest solution for the torque tube seal is the Okie seal. It is not hard to replace but is time consuming. As mentioned by Forty9 above you should check your differential fluid to see if the torque tube seal is the culprit.
The axle seal is a bit more work. But before you take it on you should check to be certain your axle vent is not blocked. This would not allow pressure to vent and could force fluid thru the seals.
