Description	Manufacturer	Purchased from	Installed by
ARB air lockers front and rear	ARB	Four Wheel Parts Wholesalers, Denver, CO	Four Wheel Parts Wholesalers, Denver, CO
Moser 35 spline axle	Moser	Four Wheel Parts Wholesalers, Denver, CO	Four Wheel Parts Wholesalers, Denver, CO
Switched from 3.54 to 3.73 gears Front and Rear (obviously had to do both)	Spicer	Four Wheel Parts Wholesalers, Denver, CO	Four Wheel Parts Wholesalers, Denver, CO
Mag-Hytec rear differential cover	Mag-Hytec	Mag-Hytec	myself

Overview
I decided to add ARB air lockers to both the front and rear differential, to get the best of both worlds: an open differential in normal driving and fully locked differentials when the going gets tough.

Four Wheel Parts has been one of my major parts suppliers, and they rebuilt my differentials, added ARBs and changed the gearing. Overall, they did a good installation, although I did notice seepage at both the front and rear pinion seals after the ARB installation.

ARB Air Lockers
I've only used the air lockers a couple of times, and they have performed perfectly every time. Without them, I would have been jacking, digging and winching on a couple of occasions. In January 2000, I was driving a four wheel drive trail near Great Sand Dunes National Monument in Colorado. We were crossing an ice covered stream and when we tried to climb out of the far side of the stream, we lost traction. Without the lockers I couldn't move forward or backwards. A simple flip of the air locker switch and we drove out.

The factory axles had to be replaced in order to install the ARBs with Moser 35 spline axles that should also be stronger than the stock axles.

Gearing
The 3.54 gears on the stock truck were fine. After switching to 255/85/16 tires which are 33 inches diameter compared to about 30 inches with the stock tires, my acceleration declined significantly. After adding a utility box and camper and approaching a weight of 10,000 pounds, the EarthRoamer® had become the EarthCrawler. While Four Wheel Parts had the differentials apart for the ARBs, I had the gears changed to 3.73 and was very happy with this gearing. I had good highway cruise speed, and in conjunction with the BD low stall speed torque converter, around town acceleration was good. For a 10,000 pound truck with a stock engine, my truck performed well.

Now that I've changed to Michelin XZL tires that are 36.4 inches in diameter, the 3.73 gearing is once again too high, so I plan to change the gearing to 4.10.

Aluminum Differential Cover
The Mag Hytec differential cover provides more capacity, a drain plug, a dipstick, and better cooling. On top of all that. they look cool. The dipstick alone makes this a good investment and I'm happy with the purchase.