When my 4l60e **** the bed on me back in the spring, I bought a complete donor truck to do a manual swap, and it also had a manual transfer case. As has been stated, the mechanical aspect of everything is easy and bolts right up. Really just tear out the old t-case and install the new one, cut a hole in the floor and bolt it all together. The electrical is a little trickier, and I guess it depends on how picky you are. If I remember correctly there's two plugs on the manual case itself, as opposed to I believe three on the auto. One is your speed sensor which will plug right in, and ones the 4wd switch. This tells the truck, and consequently the front axle it's in 4wd and let's it engage. Now, I wasn't terribly picky with the lights and whatnot, because I opted to junk the chunky floor cover and use a rubber shifter grommet like everything else has. So I didn't utilize the light. If you wanted to, they receive power off one of the pins on the differential actuator. I skipped all that to make it simple, ran power to the switch on the t-case, then to the actuator and it applies when it needs to, in 4 hi & 4 low. Don't remember the exact wiring off the top of my head. Wasn't hard once all the gremlins were figured out.