[rgmax]

I retro fitted both front and rear factory lockers into my '96 a few of montha ago. Here are some of the highlights:

1) The rear locker bolts in with only a small notch required to clear the actuator arm. Takes less than 5 min with a die grinder and carbide bit. You will also have to replace some of the studs with longer ones (4-5 I dont remember exactly) . The passenger side axle is also different( shorter). The wiring harnesses (2) will need to be replaced between the diff and where they enter the left rear quarter. You will have to fabricate a 5 wire harness to bridge the gap to the main harness connector in the drivers side kick panel. I scavenged pins out of the connectors on the discarded harnesses, soldered them to my "bridge' harness and inserted them into the empty holes in the existing main floor harness connectors. Thats it for the rear, pretty easy.

2) The front is a more complicated. This is the time to repack the birfs, bearings, replace seals, etc since the axles have to be pulled.
The notch required to fit the diff is much larger that for the rear, I used a combination of cutoff wheel and die grinder. Enought metal remains on the sealing area that I decided not to weld up this area. So far no leaks, but having it welded would be best.
Unlike the rear, 4 studs need to be moved which of course require holes to be drilled and tapped. This is by far the trickiest part of the mod. I removed the 4 old studs, bolted in the new diff and used a transfer punch to mark the new hole locations. Using a hand drill with a fabricated alinement fixture I drilled then tapped the 4 holes. There is little room to work with the housing in the truck. If I had to do this over I would have removed the housing, had it welded and used a drill press for the new holes.
The front diff wiring harness connects with no problems to the existing harness on the passenger side fire wall.

All thats left is to plug in the locker ECU in the passenger side kick panel, add the diff lock indicator bulbs/holders into the dash and add the diff selector switch.

I bought the diffs, wiring harnesses, gaskets and a few other odds and ends new online. Some of the other items that would have been expensive new like the locker ECU and axle I got from salvage yards. Its possable to get all these parts from salvage yards making the mod fairly inexpensive.