The 2003 Toyota 4runner comes with a highly sophisticated traction control system (ATRAC). The beauty of this system is that it really works. It's been trail tested and it is much more capable than any older version available. Toyota's engineer really fine tuned this system for the average owner that the need for a locker has become extinct. Unfortunately, if you are an extreme offroader and love to hit the more difficult trails, aftermarket lockers are a must.

Rear air locker....

After looking at the raw data on the rear diferential of the 2003 Toyota 4runner, I quickly learned that this rear differential was the same as the 8" differetial found in the previous generation 4runner. This meant that the rear locker available from ARB would fit the 2003 4runner. With this in mind, I enlisted the help of T and J Performance of Orange, CA to help with the installation of the rear locker. The installation of the ARB Rear locker (part number RD23) proved to be a snap.

ARB supplies all of the switching components with the locker. Therefore I used the ARB supplied air compressor switch to give that "authentic ARB" look. Naturally, this switch controls the ExtremeAire Compressor. Instead of using the ARB rear locker switch I decided to go with the 80 series Landcruiser switch. It is the dial switch located on the other two images. The reason why I went with this look and feel instead of using the ARB switch is because I wanted to preserve and maintain the same stock Toyota look. The only downside on using this switch is that it is not back lit so you will not be able to find the switch in the dark.

List of equipment:
84725-60020 (80 series LC Locker Switch)
ARB RD23 Rear Locker

Air Compressor....

Additionally to power the air locker, the need for a quality compressor was needed. After searching online for the best solution, I felt that the ExtremeAire Compressor was the best product available for my needs. The 100% duty cycle is what was drawn to me and I just went with it. This compressor can air up a 33" tire from 15psi to 36psi in less than 90 seconds!

The compressor fits perfectly as shown and looks as if it was meant to fit in that spot!

Power Steering Cooler....

Upgrading to 35" tires meant that the stock components will be tested to it's upper limits. With this in mind, the need to add a power steering cooler was a must. Simply picked up a simple power steering cooler from Summit Racing (approximately $30-$50) and installed it on the same day. The cooler itself is located in front of the radiator and next to the transmission cooler. The power steering resevoir also has been relocated to the front of the radiator as well to free up room for the additional battery.