When it comes to axles in general, it appears that there is no hard and fast set of information. They appear to be tied to the vehicle VIN, and the number of possibilities is great. If you do a google search for '1999 Dodge Dana 60 Axle Nut', it yields a plethora of conflicting information LOL. You might even have a nut with notches (4 or 8), or a nut with 'rounded' corners. There doesn't seem to be any truly definitive information. Good Luck.
I can't be 100% sure without actually measuring the nut, but it is the only socket that I can find listed for the Dana44 and Dana60, and is the only socket of that size range in my tool box. The available information on these rear ends is pathetic at best, except for setup info. I would recommend measuring the nut first to make sure it is in this range.
Hey there , just checkin in to see how your doing enjoying the site . Theres a ton of information and over 23,000 members . So if theres anything you need , you can post up or shoot any of us Z staff a message and well be more than willing to help . Talk to ya soon . Tom