I've done it, but it was out of necessity. The truck got dunked at attica and shorted out the t-case computer. I myself would pay the money for a switch if thats all that's wrong with it. The 4low button doesn't do any thing to the hubs persay, it tells the computer to shift the case to low range.
Here's kinda how it works. You push the button, that tells the computer you want 4H or 4L, the computer checks the interlocks to make sure the tranny is in neutral (for going to or from 4L) and then checks the indexed position the case is in. If all is right it applies power to the electromagnetic clutch that brings the front driveline up to speed (2H to 4H shift on the fly) When the sensor tells the computer the shaft is spinning it actually shifts the fork in the case and she slides into 4X4 mode. It shifts until it gets to the next index spot and then it stops. Those index spots in the little housing on the end of the t-case shift motor actually serve as limit switches as they interact with the computer.
Here's what you loose:
1. Shift on the fly capability, this doesn't matter if you have manual hubs, cause if the hubs are in, the driveline is already spinning. If the hubs are out why would you shift on the fly to a dead drive axle? If you shift on the fly and the driveline is not spinning there's a good chance you'll grenade the case.
2. No more limit switches, you have to control how far the case shifts by using the switch. Going to 2H you can watch the volt gauge, you'll know when the motor hit's the end of it's travel, trust me. Same going to 4L. 4H is another story, there isn't much engagement area in the shifter travel for 4H and the shift motor moves the gear real fast. So unless you take the extra time to wire up the dash lights you don't have a clue when it's in 4H. Mine kicks out of 4H sometimes cause it's not in right and I wired my lights into the system.
What you need if you decide to do it: a 6 pole 3 position switch rated to 50 amps, spring loaded to neutral (center position), a multi meter and probably about 8 hours to trace all the wires to figure everything out and fix it.
It's really kind of a pain in the butt, but it is workable.
Like I said in the beginning, if it's $100 for the switch I'd get one, or better yet try to find one in a bone yard. In my case it was $300+ for the computer, didn't have the money, and stood a real good chance of it happening again next time I run attica.
Just my .02, good luck
