6. Here the housing has been gutted of the stock axles, gears, shims, and bearings and the new Superior pinion has been installed. | 
7. Before the ARB Air Locker could be installed, the housing was drilled and tapped for the air fitting. | 
8. Next, the case spreader was adjusted and the new ring gear and ARB Air Locker were lifted into place and shimmed. |
9. With the right shims chosen and an acceptable gear pattern in place, the bearing caps were tightened. | 
10. We then routed the Air Locker's hard line to our new hole and connected it to the soft line. | 
11. With a Kilby onboard air setup already in place on our JK, we tapped into an extra bung on our 2.5-gallon tank instead of using the ARB compressor to activate the locker. We'll cover the Kilby OBA in next month's issue. |
12. With everything in the differential housing tightened up, we installed Dynatrac's stout rear cover. | 
13. Once the differential was buttoned up, Mel slid the new 35-spline axleshafts into place for a perfect fit and newfound beef. | 
14. Here is a shot of the preproduction version of the wiring kit, available from Off Road Evolution. This setup allows the factory switch to operate the new ARB rear locker exactly as if it were the stock electric locker. |
15. With the rear axle finished, we swapped the 4.88 gears in to the front axlehousing, along with the new 32-spline chromoly axles and factory rear locker. | 
16. Lastly, the driveshafts, sensors, and brakes were reinstalled. Everything was torqued to the proper specs and double-checked. With fluid added and a successful road test behind us, we are well on our way to wheeling impunity. | |
Results
After doing the calculations, we decided on the 4.88 gears to complement our 35s, knowing that the extra leverage over a 4.56 would be needed for the stock 3.8L to move the heavy Jeep, especially after increasing the rotating mass and decreasing the aerodynamics. After 5,000 miles, we couldn't be happier with our selection. With the six-speed manual, our JK cruises just above 70 mph at 3,000 rpm, still pulls in a hair over 16 mpg (if we really behave), and has gotten us all over Moab with us never wondering once if we should have gone for a different ratio. In fact, we think this is a perfect combination of streetability, trailability, and every day comfort. Next up, we'll have to figure out how to get our lockers to operate in anything other than 4-Lo.