Rear Traction Device - Which to choose? As you probably have figured out by now, my analytical personality caused me to study every option for months in as much depth as possible. When my daughter was around 3-6 months old, she would only contact sleep. So I had literally hundreds of hours of having her asleep on me in a chest carrier, as I walked in circles around in a dark room - endless time to read and watch everything I could find on Montero traction devices.
Option 1 - Mitsu LSD - These can be found on other USA Gen3s, including some 2001-2002 XLS models with 4.90s so ideally those would be the ones to target.
Pros: Cheapest, easiest to install (don't even need to open up the carrier, just install the whole unit), tried and tested, always on.
Cons: Least effective option. Don't get me wrong, they are a huge help and the Aussies have developed a way of wheeling where you use your handbrake to help engage the LSD on obstacles but at the end of the day, if you put a wheel in the air it's not going to perform like a true mechanical locker.
Option 2 - Mitsu Rear Air Locker - Gen3 Monteros in South Africa, UK, the Middle East, and a few other places had the option to come with a factory rear air locker, just like our familiar Gen2 SR models. I contacted several junkyards and the cheapest source with shipping included was consistently yards in the UK. You're looking at around $600 shipped for the basics: Rear Carrier Assembly with Air and Electrical pigtails (technically all you need is the locker, air line, and electrical harness but then you'd have to drill holes into your existing diff housing) and Air Compressor. I'm 95% sure that this is all you need to get the unit up and running with your own wiring to a simple switch in the cabin. To get the rear locker to interface with your dash lights and factory settings (only work in 4Lo) then you would need an electronic control box module thingy, factory switch, and I suspect a lot of the wiring harnesses.
Pros: Cheap compared to new lockers, Mitsu quality, Manual Selection, Fast to engage and disengage, 100% locked connection, bolts right up/easy installation (in theory since to my knowledge only one US Montero owner has ever done the swap and he lives overseas now and is very hard to reach), low pressure system so less likely to leak than the high pressure aftermarket units.
Cons: Used units only; coming from overseas so no way to really test it out and if it doesn't work you might be screwed since return shipping would not be worth it; you'll be a guinea pig since this swap has not been well documented; the air compressor is hard to find and although there is a very good chance our US Gen2 SR air compressors will work, the part numbers are different and no one has tested it to confirm; most of the parts will have a good amount of rust on them being from the UK and being old junkyard units; air locker but the low pressure system can't be used to air up tires.
Note the locker air line and wiring harness going into the passenger side of the rear diff:
F47C is the factory diff code you want:
Air compressor (located under the vehicle, right next to the rear diff so that's why they are usually rusty):
Electronic control box (i think this is optional if you don't want it to tie into your existing 4x4 system/dash lights) :
Diagram:
Here is the info you'll need when ordering from abroad:
- Complete Rear Differential unbolted from the rear driveshaft and from the rear axles. The air hoses and electrical connectors need to be intact. (See photo for an example of what this looks like)
- Rear Diff Air Pump/Compressor unit - MR953484 (this is bolted right next to the rear diff under the vehicle and not inside of it like on the Gen2 SR).
Optional stuff:
- Electronic Rear Diff Control Box - MR305675
- R/D Lock switch from interior switch panel in center console - MR402471
- Wiring harnesses????
Option 3 - ARB Air Locker - This is the most common way to go in the USA when Gen3 guys want traction help. I've never had an ARB locker but have heard of so many polarizing stories that I don't know what to think, seems you either love them or hate them. I've had other ARB products and for the most part they are good quality but there are literally thousands of posts of people who have had locker failures. Typically it is from either the o-rings inside the unit leaking (not supposed to happen for 10 years but many experience this much sooner and some, like the AZ Crew never have), and the air lines leaking. The air lines the unit comes with are just plastic and can melt if too close to a heat source or crack, or pinch, etc. You can buy an insulating/protecting loom for them for around $80 or you could get real creative and run solid metal air lines since the Gen3 doesn't have a rear diff that moves much.
Pros: Very common with endless customer service and aftermarket support, Warranty, strong and high quality unit with the exception of the o-rings and air lines, you could pair the rear locker with a front locker from ARB as well if desired and run them off the same ARB air compressor, Manual Selection, 100% locked connection, can air up tires with the compressor if you get the middle or top of the line compressor units.
Cons: Expensive at around $900 + $175-$550 depending on which model air compressor you get + $80 air line protecting looms + (optional expense depending on which set up you go with a lot of guys run the $70 manifold kit when pairing the twin compressor for tire duty and air locker use.), needs to be set up by an experienced ARB installer since there are a lot of ways it can go wrong and lead to reliability issues, some state that unlocking and locking the unit can be a pain depending on how your vehicle is positioned and like all air lockers I've ever seen you might need to move forward and back a bit for it to lock/unlock which can be precarious in certain situations that 99% of users will never experience so it's kind of moot, Air Lines/Seals to worry about.
Option 4 - TJM Air Locker - Another popular Aussie brand claims to be better than ARB because it does not use O-rings to establish an air seal in the unit and instead has this piston/actuator thingy. They can be had for $300 less than the ARB unit too. The TJM air compressor is like the base ARB one and just runs the locker and I was not able to verify if a bigger ARB compressor can be used with the TJM unit to run both the locker and air up tires.
Pros: Warranty, used on other vehicles in the US though I've never heard of a US Montero running one, significantly cheaper than ARB.
Cons: You'll notice I didn't list reliability in the Pros section despite that being TJM's most touted advantage over ARB. That's because of this forum post:
https://forum.ih8mud.com/threads/was-deal-thread-now-tjm-locker-install-thread.964929/
Basically, Summit Racing cleared out all of their TJM stock a few years ago at an insane discount and a bunch of Toyota guys grabbed lockers for their Land Cruisers. Problem is that almost all of them had actuator failures soon after and some had air line fitting failures too. Was it just a bad batch of actuators that Summit Racing had or is it a design flaw?
Cons contd - same as ARB mostly, air lines to worry about, must be set up by a really really good installer, and a little bit of trickiness can sometimes happen with locking and unlocking.
Option 5 - Chinese ARB Clones - Although several US guys have reported good things, I'm not taking the chance on this build being that it is not a budget build and even if it was, the diff is not something I would ever go cheaper on, so I didn't research these options in depth and never seriously considered them.
Option 6 - Harrop E-Locker - Built under license in Australia, the Harrop unit is an electromagnetic unit that traces its lineage to Eaton E-Locker of the Detroit and Trutrack locker fame, but today's Harrop unit is a newer generation that has had some improvements over the original Eatons.
Pros: Popular in Australia with excellent reviews (most guys put them in the front diff if only doing one since many of the Pajeros over there came with a factory LSD in the rear), No Air Lines or O rings or Pistons to worry about, Nearly instant lock/unlock (1/8-1/4 wheel turn), Manual Selection, 100% locked, No compressor needed, Warranty.
Cons: Expensive (at $1500 it will be in line with, maybe a little cheaper or more expensive than ARB depending on what compressor you go with and who installs it), cannot air up tires with it, guinea pig (no one is running one in the USA to my knowledge, Unwanted unlocking of the locker will be something you come across when researching these because if you are locked but roll backwards (down a hill, or you put it in reverse) the locker disengages then reengages automatically which is not ideal.