When I first got my 4Runner, I had to lock/unlock the hubs with pliers because it was too difficult to turn by hand. I figured a hub rebuild was in order. There are several excellent write ups on the internet for Toyota Aisin hubs. Here are some links:
Pirate4x4.com
4x4Wire.com
Off-Road.com
After following procedures from the above links, my hub dial now turns freely with ease. When I disassembled my hubs, they were bone dry and there was lots of surface rust. I cleaned everything up and applied a light coat of grease. Here is what they looked like
| |  | | | Nice rust on the inside which was making the dial hard to turn | | |
| |
| |
| |
| |
