Project 4Runner



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I finally stumbled upon a drive train donor for the 4Runner, a 4x4 1996 SR5 w/3.4 and automatic transmission.  It was drive able and the engine sounded great at idle and when driving. The parts truck was rolled by the original owner and was for sale with approximately 129k miles on it.  It has a number of newer parts on it, notably the previous owner had recently changed the water pump, timing belt, brake pads and put new shocks on the chassis.  Another bonus - the factory 4:30 gears and electric locker in the rear differential. 

So far my 4Runner's 3.4L engine is running well at 330k miles on the original chassis/engine but there are some issues that have been accumulating -

Engine - Running well but I get the occasional P0446 code that pops the check engine light. After checking the easy stuff I am fairly certain the problem lies in the brittle charcoal canister. The engine also has some sort of oil leak with the main culprits being the oil pan gasket or power steering pump. The original alternator died a few weeks back so this parts truck is too late for that but I have been thinking about swapping out the starter, power steering pump and A/C compressor at some point as preventative maintenance.

Braking System - The ABS light has been on for a while.  Again, most of the easy stuff to check/replace has been tried so part swapping is the next step. The parts truck has a functioning brake system with no warning lights so the ABS computer,  ABS sensors, pump and master cylinder are available for replacing their older counterparts in my 4Runner.  Since the parts truck has better differentials, swapping the front and rear driveline components makes total sense and would provide fresh brakes, a selectable locker for the rear end, and a small gear reduction in high range (my truck has the factory 4:10 ring & pinions).

Interior - Lots of missing/broken items, mostly annoying stuff that is too expensive to replace with factory parts such as cup holders, dash clock, etc. The parts truck interior is in good shape although the front portion has been exposed to the elements for a while after the previous owner cut off the front portion of the roof.

I decided to get the parts swap started by getting the axles swapped.  This would allow me to start enjoying the benefits of the factory selectable locker and the 4.30 ring and pinions from the parts truck. A couple things to note along the way.

1. Discovered the rear axle from the parts truck had new brakes and drums on it.

2. When swapping the rear axle I realized I had a lift spacer and the lifted Land Cruiser springs in the back of my 4Runner. Pulling the extra lift spacers that were above my coil springs dropped the back 2" and allowed me to lower the front the same amount.  The truck should be able to get to factory alignment numbers now.

  3. With the front differential I was finally able to see the source of the oil leak on my 4Runner was the high pressure line coming off the power steering pump. All along I was convinced it was the oil pan gasket.  I swapped the pump and high pressure hose from the parts car.

4.  The lower mileage front driveshaft was also swapped into my 4Runner.

5. With the front and rear axles installed I was able to start swapping parts to see which one would shut off the ABS light. The first part I tried did the trick: culprit appears to have been the ABS computer.

6. The charcoal canister assembly was also replaced in my truck with the one from the parts truck. So far no check engine lights after approx 400 miles. I had suspected hairline cracks in my old canister.  

So with my 4Runner drivable again I was able to turn my attention to wiring up the factory electric locker.  My 96 4Runner did not come pre-wired for the e-locker computer, e-locker switch or the dash light so this was a worst case scenario. There are several write-ups on the internet on ways to wire in an e-locker either with the factory computer or custom harnesses so I will only cover the unique things I ran into. I will say, this PDF was the best reference I found that matched what I was seeing. Since I had a complete donor 4Runner, plenty of time and a desire to make this install as factory as possible I chose to harvest what I could from the parts car for the harness vs. paying for a custom harness.

The factory e-locker harness starts at the rear diff and runs up and over the gas tank. It is attached to the top side of the factory gas tank which requires you to drop the tank to free the harness. The harness then enters the cab thru a grommet/cover arrangement under the passenger rear seat, ending at a connector once inside.  From there the elocker wires  join the main bundle that runs along the door sill forward to the drivers side kick panel where the wires then enter another connector.  Anotehr short run of wire from that connector and the e-locker wires terminate at a small E-locker computer behind the driver side kick panel.

 To make a single harness and separate the e-locker wires from the main bundle I cut out the connector where the wires entered the cab which allowed me to extract the e-locker wires out of the main door sill bundle. I then soldered the remaining elocker wires back to the rear section of the harness after pulling the rear ABS sensor wires.  Next I cut the wires at the connector by the the drivers kick panel and reattached them to the connector  from the elocker computer. I was left with something that looks like the above, grey e-locker connector on one side and a white connector for the e-locker computer on the other. I did have two extra wires coming off the e-locker that did not seem to go anywhere - a white/black stripe and white/red stripe. Both wires ended inside of what looked like the factory wire sheathing and were cut clean about 18inches from the elocker connector. These ended up needing to be grounded before my e-locker would function.  I saw no mention of these two wires in any of the write-ups I saw. 

Once I connected my new e-locker harness to the locker, I ran it up to a factory grommet that was close to the drivers side shock mounting point. This brings the harness in just behind the rear seat. The extra white/black and white/red wires were grounded at the factory tie down threaded hole. From here it is a straight shot along the door sill to the factory e-locker computer.

The other wires coming off of the e-locker computer were all pretty self explanatory.

Green/yellow went to one side of the factory locker switch, black/yellow from the other side of the switch to a 10amp fused circuit.

Black/yellow from e-locker computer to 20amp fused ignition circuit.

White/black to ground.

Green/orange spliced into green/orange wire at junction box behind and to right of steering column.

Blue/red to ground to bypass the 4low switch. This allows locker to be engaged in 2wd and 4high.

The tricky wire was the Yellow/blue wire which needed to get tied into the gauge cluster to illuminate the diff lock light in the dash.  Turns out Toyota chose to save a cent and left the wire out of my dash cluster connector. After having no luck trying to pull apart the parts truck connector I just cut mine off and soldered in the parts truck connector and then soldered the yellow/blue wire to e-locker computer harness. I also had to add a bulb to the open socket behind the diff lock indicator.

As others have mentioned the 4Runner locker switch has an internal light but the connector does not have sockets for the needed ground/power. I found a connector under the center arm rest with the correct sized sockets (see above) and cut them free from the connector with my Dremel (leaving several inches of wire attached). I was then able to insert the sockets into my switch connector and then tie one side to the dash light circuit and remaining to ground. 

With power to the ignition I now get a nice buzz/click when I engage/disengage the locker via the switch. I jacked up and confirmed the rear wheels were locked. Since I was coming from a Lockrite locker this modification is actually most noticeable on the street. Gone are the little wiggles the truck would make when getting on/off the gas at speed as well as the clicking when going around corners. Off-road this locker is much more like a spool (which it is), in that I mean it tends to push the truck more in corners where the Lockrite would disengage.

The lower ring and pinion ratio is also noticeable. I wasn't expecting much but during hard acceleration the shift point is now raised just enough as to not bog down in the 1st to 2nd shift. I also notice the truck climbing the familiar hills leading up to my shooting spot without needing to drop out of overdrive as much.

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