Hy Bryan Buser, when you fix your tranny leaks and top up your trans lube, check your differential lube level and top up if required. Then take your truck for a couple of drives and recheck your diff. oil level, [make sure to check it at the same temparature that you filled it at] if the level is up in the diff, and down in the trans then the seal in the torque tube is leaking, hope that helps.
