I upgraded to manual locking hubs after wanting to do it for several years. Now, “upgrading” to something that makes you get out of your car to use 4 wheel drive seems a little crazy to most people, but I see it as an upgrade since they are considered stronger than the stock automatic hubs and there is no question if they fully engaged or if something is wrong. Listening for the “click” and not being sure you heard it is a little unnerving. Also, I am only engaging 4-high and 4-low when I am going somewhere off road, so getting out and turning the hubs isn’t that big of a deal.
If you would like the service manual, it goes into detail disassembly, service, and reassmbly of the stock auto hubs and the Aisin/Asco manual hubs:
Before installing the hubs there are several choices of what brand to get. The OEM hubs are made by Aisin (or Asco and I have read that Aisin bought Asco) and it seems that they are considered the best. The other two brands are Superwinch and Warn and then there a few other brands that are significantly cheaper, AVM , Rugged Ridge, and another brand that is on eBay that looks like Aisin but without a brand name. Since Aisin are hard to find, I didn’t want to buy a random brand, and Superwinch seemed cheaper, I went with WARN 61385 hubs.
The only downside is that I bought them on eBay and the seller shipped the original box without any tape and the hubs fell out in transit. After some emailing they finally shipped me a replacement set, but when it came the box only contained the hubs, but no gaskets or bolts. Maybe that is normal or maybe they didn’t include it in the box. Either way I needed those parts and got the WARN 61693 Service Kit that has the missing parts.