Mitsubishi Air Locker installation Short Cuts

[ 4x4Wire Page | Mitsubishi on 4x4Wire | TrailTalk Forums | Mitsubishi Projects | Mitsubishi Reviews | Mitsubishi Tech | 4x4Wire Gallery | 4x4 Trails | Site Index ]

Edited by Phil Hansford, Sept 27th, 2004

Vehicle: GenII Montero/Pajero, others similar

Why not an ARB? ARB air lockers are pretty expensive here in Italy: 800 for the locker, 300 for compressor, switches, etc., 250 for install (ring & pinion setup). More, there are some hidden costs: here in Italy ring + pinion setup is not common work, so you have to find somebody that can do the work, take your diff to him (not on the weekend of course), lose a couple of working days, hope that he knows what he is doing...

What do I need?

I decided that my locker should act exactly like a factory locker, so here is the shopping list:
-Mitsu axle, or at least, the 3rd member and the left axleshaft
-Mitsu air compressor, or any 12v compressor with a pressure limiter (my locker engages from 0.9 to 1.2 Bar, maybe less when installed and filled with oil...)
-Mitsu dash switch
-Mitsu locker ECU
-Mitsu electric cable from locker sensor to body, or any 12v cable and some cut and paste...
-2.5m of air line.

Can I mount the complete Mitsu system in my Paj?

Yes, but know that electric parts are different (or at least located in different places) from LWB/SWB, from '94 and earlier/'95 and later (depending on where they are sold). My electric parts came from a '95 SWB and fitted in my '97 LWB. However, do this simple check: remove the little plastic cover at the left of the electric plug (the one in the dash, under the radio bay) and you should find a little connector.

Good old LSD axle shafts axle shafts
The original LSD Axle shafts from the front Axle shafts from the rear

Once the parts are in place...

The whole work can be done in a day, but you should decide to do the 3rd member swap one day and the other work later. Uh, 3rd member swap? Yes, not a complete axle swap. My main reasons were:
- I wanted to check the used diff before installing
- I didn't want to disconnect (and purge after reconnecting) brake lines (and I was wrong, left axleshaft must be replaced...)
- In the used axle many parts were missed (brake lines too) and the handbrake cables were cut
- Air line and sensor fittings were in the 3rd member, so no mods were required to my axle
- I'm not sure, but a complete axle swap should require more work and effort...

Locker Detail_locker_unlocked Detail_locker_locked All_done
The Factory Locker Locker unlocked Locker locked All done!

3rd member swap

- park your truck, in 1st low, with the centre diff. locked- don't engage your hand brake
- raise your truck from the axle, and place jack stands under the frame (uh, there aren't jackstand in my photos...)
- drain the diff
- pull tires
- unbolt and remove brake caliper (without disconnecting brake lines)
- unbolt and remove brake rotors (maybe you have to bolt something in the holes to take it off)
- unbolt and pull out for 10/15cm axle shafts
- unbolt and remove the drive shaft
- unbolt and remove 3rd member- a couple of notes: the unbolted 3rd member will stay stuck in the axle, so start prying it out with a big screwdriver starting from the lower left quarter (looking from the front): near there you should be able to find a place where you ca insert the screwdriver between axle and 3rd member- pay attention, the 3rd member is quite heavy, having your sway bar installed can help you.

Repeat (where needed) the same operation for the donor axle- when you have both 3rd members apart, check by hand if they have approx the same freeplay- more, check if the locker works (don't use too much pressure) and if the sensor works. Don't remove the sensor (unless it's broke...). If you simply rebolt it in, you partially lock your diff- reinstalling the sensor without removing the carrier from the 3rd member requires a lot of patience and a bit of magic... As you can see from photos, the locking mechanism uses square teeth, but there is some sort of syncro gear too hidden in the carrier.

- clean the axle housing, and the old loctite
- put new loctite on the 3rd member, insert it in the axle housing, and rebolt
- remove axle shafts, at least the left one- the Mitsu locker uses a shorter (+-15mm) left axle shaft - the right axle shaft is the same length- removing axle shaft requires removing the park brake cable (and removing the park brake cable require disconnecting brake lines...), so I've replaced only the left one

Now it's obvious, you have to reinstall all the removed parts. Don't forget to refill your diff with oil, not for LSD.

Now install the other stuff.

Dash Switch

Remove the little plastic cover at the left of the electric plug (the one in the dash, under the radio bay): you should find a little connector- connect the switch and press it in the hole.


In the LWB the compressor must be installed under rear seats, right side (where you can find the jack). You should find a little (2 wire) connector. Note: this connector sends power by command of the locker ECU, so you can install a common 12v air compressor with a pressure limiter (I think 1.2bar is still a safe limit, since I've pumped my diff up to 2bars to check for leaks).

Locker ECU

This is hard (can we say PITA?). In the LWB the connector is located in the rear left quarter of the car, and my Paj has the 3rd row of seats... So first remove the left seat, then the big plastic cover. I know, it's a lot of work, at least 15 bolts to remove. Now you can find an hole near your rear left corner. The connector is somewhere inside this hole... In my Paj there is another hole, filled by the seat belt roller, and if you have little hands maybe you can try this way- however for me it was pretty hard to take off the connector. Once you get the connector, remove the plastic cover on it (it has a wire for short-circuit some thing) and plug in your locker ECU. Then you can reinstall everything (if you can remember where all the bolts go...).

Mitsu electric cable and air line

Pretty easy, but you must go under your car once again. Of course, one side of the electric cable must be connected to the locker. The other connector is on the frame, near the lower arm front bushing. Now the air line. As I installed it (and the electric cable follow it), it starts from the locker, then goes to the rear of the axle, follow the lower arm and then enter the car under the rear left wheel well. You can see a rubber cap with some wires coming from it. I've simply made a cross cut in the rubber cap and pressed the air line in it - now reaching the compressor is easy.

Locker light on the dash

If everything is well connected, the locker light automatically lights up every time you turn the key, and every time your locker is locked.

Related Links

Trending on 4x4Wire TrailTalk Forums

New Topics on TrailTalk
Gen 1 Trailer Hitch and Owners Manuals
by Kookster97 - 06/17/22 12:37 AM
Gen 2 UCA extended upper ball joints?
by Colombia - 05/24/22 03:28 AM
Blown Head Gasket - could use advice
by Runner-Man - 05/23/22 01:58 AM
suzi the psychic
by - 03/26/10 06:59 AM
Recent Posts on TrailTalk
Gen 1 Trailer Hitch and Owners Manuals
by Mudraider - 06/17/22 04:50 PM
Gen 2 UCA extended upper ball joints?
by Mudraider - 06/15/22 07:00 PM
suzi the psychic
by rascott - 06/14/22 01:47 AM
Blown Head Gasket - could use advice
by Snowtoy - 05/30/22 06:11 AM

4x4Wire Social:

| 4x4Wire on FaceBook

OutdoorWire, 4x4Wire, JeepWire, TrailTalk, MUIRNet-News, and 4x4Voice are all trademarks and publications of OutdoorWire, Inc. and MUIRNet Consulting.
Copyright (c) 1999-2019 OutdoorWire, Inc and MUIRNet Consulting - All Rights Reserved, no part of this publication may be reproduced in any form without express written permission
You may link freely to this site, but no further use is allowed without the express written permission of the owner of this material.
All corporate trademarks are the property of their respective owners.