1997 Toyota 4Runner SR5 - IFS ARB Air Locker Install and E-locker Retrofit

The ability to install dual selectable lockers was an important factor for me in deciding to get a 4runner in the first place.  Since I was not able to find a 3rd generation 4runner with the e-locker already in the rear diff, I debated about going with dual ARBs versus retrofitting the e-locker.  The novelty of the e-locker and lower install costs swayed me in that direction. The ARB in the IFS was a no-brainer.

I purchased the 4runner in October of 2002 and by January of 2003 I had a used e-locker 3rd with 4.30s on the bench.  My truck came with 4.10s and the gear-ratio improvement was appealing because I run 32" tires.  By March of 2003 I found a used IFS diff with 4.30s.  Through the spring and summer of 2003 I installed on-board air and prepped the e-locker wiring.  I had a shop install the ARB Air Locker into the front diff and by fall I was ready for plug and play installation.

The install took around 18 hours of wrenching, but we were able to get it done in one weekend (starting Friday late and finishing Sunday early).  That included pulling a CV axle to replace a CV boot and running into town a couple times.  I did most of the wrenching, but had the expert help of my brother, who supplied the air tools and did all the work on the rear housing for the e-locker retrofit.  Thanks Jon!  Detailed instructions for the IFS diff installation and e-locker retrofit are available on the web and proved invaluable - see the web links below.

So almost a year after I proudly drove my 4runner home for the first time, my rig finally has dual selectable lockers.   I am very happy with the installation and think the ARB/E-locker combo is a great way to go.  I ran a rear ARB in another truck and so far am equally impressed by the e-locker.  It's amazing what the 4runner can climb over and up effortlessly.  Pics of the process and installation tips are provided below. 

IFS diff, E-locker 3rd (both with 4.30s), and ARB carrier on the bench	Close-up of e-locker 3rd Member	IFS diff and ARB Air Locker Carrier
Where's the diff?	IFS ARB Diff with ADD attached ready to be reinstalled	Rear housing with E-locker 3rd ready to be reinstalled
Control Center	E-locker dash indicator light - lights up when e-locker is engaged	Parts needed to hot-wire the dash indicator light if your rig is not pre-wired
Viair 450 Compressor, pressure switch, ARB Solenoid, and all the fittings	Viair 1-gallon air tank tucked in ARB bumper	Testing out the lockers and checking for leaks

Some tips if you plan to do your own installation (in no particular order):

1. It took me nine months of relaxed preparation to allow for installation of both lockers in just over one day of wrenching.  Preparation included acquiring the spare diffs and installing the e-locker wiring, compressor, fittings, air tank, switches, and all the misc parts.  Unless you have all the necessary tools and expertise to do the gear setting, have the ARB installed into the diff at a shop like I did.

2. Think twice about attempting this unless you are very adventurous or a decent shadetree mechanic.  With that said, this was a relatively straight forward installation thanks to all the great write-ups.

3. Make sure your compressor and tank do not have any leaks before plugging it to the ARB.  The ARB compressor comes with all the fittings needed for the locker, but I decided to go with a Viair 450 which puts out a lot more air.  Accordingly, I had to buy the dash switch (ARB) and pressure switch (Viair) separately.  When I ordered the ARB switch, they sent me a compressor wiring diagram which included directions about how to use a non-ARB compressor - ARB customer service impressed me once again!  I also had to purchase a 1/8 BPT to 1/4 NPT adaptor (Viair) for the ARB solenoid (the solenoid and blue air line come with the locker).  www.tellico4x4.com is where I got all my Viair accessories.  I bought the compressor on Ebay.

4. Disconnect and unbolt the metal tubes from the top of the IFS diff before removing the diff to avoid damaging the tubes.

5. Never force the CV axle back into the housing.  Gentle tapping works as long as the splines are lined up and the CV is perpendicular to the housing.  Make sure you have a couple spare axle clips on hand.

6. Install a hidden shut-off switch so the front locker cannot be accidentally engaged.  Engaging the IFS Locker in 2wd will cause the front drive shaft to go from zero to your current speed instantaneously and potentially cause severe damage.

7. Shoot all bolts with PB Blaster a week before you plan to do the work.

8. Buy a E12 star pattern socket and 12mm allen wrench before starting this project.  The female star socket is for disconnecting the ADD and passenger side IFS housing from the diff.  The allen wrench is needed to drain the IFS diff and remove the third diff mount.  We also needed a 35mm socket for removing the front axle from the hub, which was only necessary because a CV boot was accidentally damaged in the process.

9. Using the factory ECU, switch, and wiring harness made it easy to wire up the e-locker.   Here's the wiring diagram I used: Locker Wiring (jpg) (modified from Ken's site below).  This set-up allows the e-locker to be engaged in 2wd and at any speed.   I still need to figure out how to disable the ABS.

10. If your truck is not prewired for the E-locker, then you will have to find a bulb/plug and a jumper wire to wire up the dash and take advantage of the locked/unlocked indicator circuit.  See picture above and write-up at Lars' site.  I found the bulb/plug and wire at a junk yard - I think it came off a Mazda pick-up.  As shown in the locker wiring diagram above, I simply ran the yellow-blue (#2) from the diff lock detection switch to the dash indicator light. The diff lock detection switch grounds the circuit and activates the dash light when the locker engages.  As stated on Lars' site, to connect the wire "Remove the lower dash cover from beneath the steering column (4 screws). Remove the black instrument bezel from around the cluster (4 screws). At least partially remove the instrument cluster (4 screws) to gain access to the brown electrical connector on the right side of the cluster (left side of cluster when looking at it from the back). Wire a connector into pin 5 of the brown connector. They are numbered on the cluster. I [Lars] simply fed some solid core copper through the connector and fed it back on itself to create a connector tab. Run the other end of the wire to" the diff lock detection switch.

11. Remove the splash gaurds and plug the axle tubes before grinding and welding the rear axle housing.  Take your time to clean out the housing really well.

12. Replace the front axle seals and inner rear axle seals.  Get a spare set of axle seals just in case.

13. The e-locker does not always engage/disengage immediately.  Turning left/right usually lines up the splines enough to get it to work.  When it works there is an audible "click" and the indicator light will come on (or go solid of you're lucky enough to have a pre-wired rig).

14. Never create a redundant write-up - see the links below for much more detailed instructions.

Web Write-ups used for the install:
Pho's Detailed e-locker retrofit: http://www.phorunner.com
Ken's e-locker retrofit - source of the awesome wiring diagram above: http://home.off-road.com/%7Ekemanuel/elocker/elocker.html
Lars' Dual ARB write-up - also discusses dash light:  http://www.larsdennert.com/4runner
IFS ARB Write-up (pdf on Steve Schaefer's site):  http://fastq.com/~sschaefer/ARB_RD90.pdf

Costs: