I stopped by Marlin's shop yesterday to get a pair of his new HD axle seals. He is really excited about these and talked to me at length about them. I won't actually get them on my rig for a few weeks still but when we were comparing them to an oem seal they really seemed like a great idea. I agree with him when he says they were just waiting to happen. They fit inside the axle tube a litttle different and they make use of almost the whole sealing surface of the axle shaft. After talking to him and him telling me about how the axle typically wears I came home and inspected several axle shafts I have and they all looked just as he described, but this seal should work on them regardless of how worn they are because it doesn't rely on the same area of the shaft as the OEM seal. I can't wait to get some miles on them. If you doubt that your shafts are true, if you run an aftermarket shaft that is heat treated after it's final machining, or if your shafts have a lot of miles on them and tend to leak then these seals could be a good solution for you.