Review on Improved Performance: National Oil Seals 710493 Axle Shaft Seal for Enhanced Protection by Darnell Nahabet

Fits Ford F250 SuperDuty early 1999. Be sure to purchase the installation tool. Yes the tool is expensive but if you try the homemade pipe flange hack people are showing on youtube you will never install this part properly and will most likely damage it. This part is the outer seal. There is a secondary inner seal between the fork and the outer edge of the axle that you will also need to replace. The part number for the inner seal, or dust seal as some call it, is 710493. The installation tool has the secondary purpose of setting the axle to the correct depth when the axle is reinstalled on the truck. If you buy this part, it's because the original failed. Unfortunately, this is no better than the original part and will probably have to be replaced in a few years. I haven't found anything better than a factory replacement. If you take your truck apart that far, you can replace all the crappy original Ford parts. Buy new Moog ball joints and universal joints with grease fittings. (The factory parts didn't have grease fittings, so they fail.)