Airlocker ARB RD90 User manual

RD90
TOYOTA 7.5”, IFS
AIR OPERATED
LOCKING DIFFERENTIAL
INSTALLATION GUIDE

No liability is assumed for damages resulting in the use of the information contained herein.
ARB AIR LOCKER Locking Differentials and AIR LOCKER are trademarks of ARB Corporation Limited.
Other product names used herein are for identification purposes only and may be trademarks of their respective owners.
ARB 4x4 ACCESSORIES
Corporate Head Office
42-44 Garden St Tel: [phone]
Kilsyth, Victoria Fax: [phone]
AUSTRALIA
3137
Australian enquiries [e-mail]
North & South American enquiries [e-mail]
Other international enquiries [e-mail]
www.arb.com.au

Table of Contents:
1
1 Introduction
3
1.1
Pre-Installation Preparation
3
1.2
Tool-Kit Recommendations
4
1.3
Assembly Type Identification
5
2 Removing the Existing Differential
6
2.1
Vehicle Support
6
2.2
Differential Fluid Drain
6
2.3
Removing the Differential Assembly
6
2.4
Checking the Current Backlash Amount
8
2.5
Removing the Differential Center
10
3 Installing the Air Locker
11
3.1
Approximate Backlash Shimming
11
3.2
Calculation & Selection of Backlash Shims
13
3.3
Mounting the Ring Gear
14
3.4
Installing the Carrier Bearings
15
3.5
Preload Shim Measurement
16
3.6
Calculation & Selection of Preload Shims
18
3.7
Drilling & Tapping the Bulkhead Port
19
3.8
Installing the Bulkhead Fitting
21
3.9
Installing the Differential Center
21
3.10
Setting Up the Bulkhead Fitting
24
3.11
Final Assembly
25
3.12
Checking the Backlash
27
3.13
Bench Testing the Air Locker
30
3.14
Reinstalling the Differential Assembly
31
4 Installing the Air System
32
4.1
Mounting the Solenoid
32
4.2
Running & Securing the Air Line
34
4.3
Connection to the Bulkhead Fitting
35
5 Mounting & Connecting the Electrical System
36
5.1
Mounting the Actuator Switch(es)
36
5.2
Wiring the Actuator System
37
6 Testing & Final Assembly
40
6.1
Leak Testing
40
6.2
Testing the Air Locker Actuation
40
6.3
Re-Sealing & Filling the Differential
41
6.4
Note For ADD Equipped Vehicles
41
6.5
Post-Installation Check List
42
7 Parts List
43
7.1
Exploded Assembly Diagram
43
7.2
Itemized Parts List
44

2

1 Introduction
3
IMPORTANT :
BEFORE ATTEMPTING TO DISMANTLE YOUR VEHICLE FOR THIS
INSTALLATION, PLEASE READ THIS INSTALLATION GUIDE IN ITS
ENTIRETY, AS WELL AS ALL APPLICABLE SECTIONS OF YOUR
VEHICLE MANUFACTURER’S SERVICE MANUAL.
1.1 Pre-Installation Preparation
This booklet is to be used in conjunction with your vehicle
manufacturer’s service manual. ARB endeavors to account for every
possible variation in vehicle model when publishing its installation
guides, and guides are updated regularly as new model information
becomes available, however, the rapid and globally varied release of
some vehicles makes it difficult to insure that your vehicle model has
been accurately accounted for. In the case of any technical
discrepancies between this guide and your service manual, we
strongly advise that you adhere to the specifications and techniques
as documented in your service manual.
Although your ARB Air Locker comes complete with all the step by
step instructions you will need to supplement your vehicle
manufacturer’s service manual and install your new differential, ARB
recommends that you have your Air Locker installed by a trained
professional. Many ARB distributors around the world have been fully
instructed in Air Locker installations by ARB, and have gained a wealth
of experience and skill from years of performing similar installations.
Once you begin this installation your vehicle will be immobile until all
steps of the installation are complete. Make sure your Air Locker kit is
the correct model for your vehicle and that it contains all of the parts
listed on back cover of this booklet. Also be sure you have
appropriately equipped yourself with all the necessary tools, parts, and
materials to complete this installation (see Section 1.2 Tool-Kit
Recommendations), and that you have allowed for an appropriate
amount of vehicle down time.
HINT : Place a mark inside each of the

symbols as
you complete each step. It is very important NOT to
miss any of the steps!

1 Introduction
4
1.2 Tool-Kit Recommendations
Below is a list of tools and supplies you may need to complete this
installation. Requirements for your vehicle may vary. Please consult
your vehicle service manual for additional recommendations.
1.2.1 Tools

Standard automotive sizes (metric and/or imperial) of sockets,
wrenches, Allan keys, and drills.

A dial indicator or other suitable measuring tool for checking ring &
pinion backlash.
NOTE : Split ‘clamshell’ type Toyota differential housings
require a long series dial indicator to check backlash.
Refer to Section 1.3 Vehicle Type Identification.

A razor knife for nylon tubing.

A torque wrench (See vehicle service manual for required torque
range)

A lubricant drain reservoir.

A slide hammer for removing CV axles.

Suitable measuring tools to measure a differential for preload
shimming. (e.g., an automotive feeler gauge)

A 11.2mm [7/16”] drill and ¼”NPT tap for bulkhead fitting
installation.

An automotive bearing puller (2 jawed) or a differential carrier
bearing puller.

A bearing press or arbor press.
1.2.2 Supplies

Thread lubricant/sealant compound (e.g., LOCTITE #567)

Thread locking compound (e.g., LOCTITE #272)

A gasket sealant or replacement gasket for your differential.

A sufficient volume of differential oil to completely refill your
housing. (see the ARB Air Locker Operating and Service Manual
for recommended lubricants)

A soap and water mixture to test for air leaks.

Teflon paste.

A selection of differential bearing shims to set-up preload and
backlash.

1 Introduction
5
1.3 Assembly Type Identification
IMPORTANT:
Sections 2 and 3 of this installation guide have been written to
accommodate two different styles of Toyota IFS differential housings:
Athe front accessed type with bearing caps (Refer to Fig.1.)
B the ‘clamshell’ type split housing (Refer to Fig.2.)
To eliminate confusion, you should identify which figure your vehicle
matches with. The section numbers within the guide that refer to the
front accessed type have been suffixed with an ‘ A’, and those that
refer to the ‘clamshell’ type have been suffixed with a ‘ B ’.
PLEASE IGNORE ALL SECTIONS WHICH
DO NOT APPLY TO YOUR APPLICATION
Figure 1.
Figure 2.
A
B

2 Removing the Existing Differential
6
2.1 A B Vehicle Support

Safely secure the vehicle on a hoist. We recommend supporting
the vehicle on a chassis hoist to keep the differential area at a
convenient working height and to leave the wheels and axles free
to be rotated and removed.

Once supported in the air, chock the wheels (if necessary) and
leave the vehicle in neutral.
2.2 A B Differential Fluid Drain

Position a fluid drain reservoir under the differential.

Remove the drain plug and drain all of the oil from the housing.
HINT : This is a good time to check for metal particles in
your oil and on the end of the magnetic drain plug
which may indicate a worn bearing or differential
component.

Once drained, reinstall the drain plug.
2.3 A B Removing the Differential Assembly

Remove the stub axles from the differential housing according to
your vehicle manufacturer’s service manual.
NOTE : Rubber oil seals can be easily damaged. Support the
weight of the axle when extracting it across the edges
of the seals.
HINT : Some Toyota IFS axles can be removed easier by
disconnecting the upper ball joint.
HINT : Toyota IFS axle stubs are retained with a snap ring
which is considered to be a one-use part. Keep two of
these clips on-hand in case the clip(s) are damaged or
sheared off while removing the stub axle. Make sure all
of the remains of the clips are accounted for so that
they cannot damage differential components and seals.

Disconnect the drive shaft from the pinion flange.

Completely remove the entire differential assembly.

2 Removing the Existing Differential
7
2.3.1 A Marking the Bearing Caps

Secure the differential assembly to a work bench.

Completely remove the front access cover.

Using a small pointed center punch, gently mark the left bearing
cap in a way which will enable you to know which cap is ‘LEFT’ and
‘RIGHT’, and which way is ‘UP’ and ‘DOWN’. (Fig.3.)

Mark the right hand cap in a similar way.
Figure 3.
HINT : Many installers choose to make one punch mark on
the left hand side of the left hand bearing cap and a
similar mark on the housing at close proximity to the
cap mark. The right hand side is then designated with
two punch marks on the right hand side of the cap and
two similar punch marks on the housing.

2 Removing the Existing Differential
8
2.4 A B Checking the Current Backlash Amount
IMPORTANT:
This step is a precautionary measure recommended by ARB due
to the fact that some aftermarket ring and pinion sets have been
manufactured to run with different backlash settings than those
specified by your vehicle manufacturer. Although ARB must
recommend you set backlash according to your service manual
guidelines, we also advise that you compare the backlash
measurements taken here to the recommended backlash settings
in your vehicle service manual. Measurements found to be
outside of your service manual recommendations may indicate
the need to deviate from those settings in order to achieve quiet
running with a good contact mark.
Refer to your vehicle service manual or your local authorized
ARB installer for more information.
2.4.1 A Backlash for Front Access Housing

Set a plunge type dial indicator on one of the ring gear teeth as in
Figure 4.
Figure 4.

While supporting the pinion gear by holding the drive shaft flange,
rotate the differential in both directions while observing the
maximum variation in depth from the indicator (i.e., the highest
value minus the lowest value). This value is referred to as the ring
and pinion backlash.

Rotate the differential center 90°and measure again for accuracy.

Record the average of all measurements.

2 Removing the Existing Differential
9
2.4.2 B Backlash for Clamshell Housing

Set a long series lever type dial indicator on one of the ring gear
teeth. Access to the ring gear teeth is gained through the oil filler
hole. (Refer to Figure 5.)
Figure 5.

Insert a large flat screwdriver or pry-bar through one of the axle
stub holes so that it wedges between the cross shaft and the carrier
body so that the differential center can be rotated by the cross
shaft, and not by the spline of one of the differential gears.

While supporting the pinion gear by holding the drive shaft flange,
rotate the differential in both directions (with the screwdriver or pry-
bar) while observing the maximum variation in depth from the
indicator (i.e., the highest value minus the lowest value). This value
is referred to as the ring and pinion backlash.

Rotate the differential center 90°and measure again for accuracy.

Record the average of all measurements.

2 Removing the Existing Differential
10
2.5 A B Removing the Differential Center

Remove the floating shaft (or ADD unit if present) from the side of
the differential housing.
NOTE : The floating shaft or stub axle is retained by the same
type of clip that was used to retain the outer stub axle.
A slide hammer may be required for safe removal.
Refer to your vehicle manufacturer’s service manual.
2.5.1 A Front Access Housing Disassembly

Remove the bearing cap retaining bolts and then remove both
bearing caps.

Gently pry the differential center forward until it comes free of the
housing.
NOTE : Be sure not to mix up the left and right hand tapered
roller bearing cups or preload shims. Later it will be
necessary to know which cup came from which
bearing and which shim came from which side of the
differential.
2.5.2 B Clamshell Housing Disassembly

Remove all bolts from around the outside of the clamshell.

Gently pry the clamshell apart and remove the differential center.

Using an arbor press, remove both bearing cups and preload shims
by pressing the face of the shims through the housing from the
outside.
NOTE : Be sure not to mix up the left and right hand tapered
roller bearing cups or preload shims. Later it will be
necessary to know which cup came from which
bearing and which shim came from which side of the
differential.

3 Installing the Air Locker
11
3.1 A B Approximate Backlash Shimming
In order to reproduce a similar preload and ring and pinion backlash in
your Air Locker to that of your existing differential, measurements
need to be taken so that a shim thickness can be calculated.

Secure the differential to a work bench.

Remove the bolts that hold the ring gear in place.
NOTE : Ring gear bolt locking tabs used on some models will
not be required on the Air Locker and may be
discarded.

Using a plastic or copper hammer, tap in a circle around the ring
gear to separate it from the differential carrier.

Remove the original bearings from the differential center using a
bearing puller.
NOTE : Keep the bearings separated so that they can be
identified as to which end of the differential they came
from.

Examine the bearing cup and cone from Figure 6. for damage or
wear and, if necessary, discard it and replace it with the same size
and type of bearing.
Figure 6.
FACTORY DIFFERENTIAL

3 Installing the Air Locker
12

Using a caliper or similarly accurate measurement method
(i.e., able to take accurate measurements within 0.04mm [0.0015”]),
measure the distance from the shoulder of the bearing journal to
the ring gear mounting face (shown as ‘A’ in Figure 6.) and record
this measurement as ‘A’.

Measure the thickness of the factory shim removed from the end of
the differential carrier (shown as ‘B’ in Figure 6.).and record this
measurement as ‘B’.
Figure 7.

Measure the distance from the Air Locker bearing shoulder to the
ring gear mounting face (shown as ‘C’ in Figure 7.) and record this
measurement as ‘C’.
RING GEAR
FLANGE
AIR LOCKER DIFFERENTIAL

3 Installing the Air Locker
13
3.2 A B Calculation & Selection of Backlash Shims
Ideally, the measurement you recorded as ‘C’ from the Air Locker
differential will closely match ‘A’ on the existing differential (within
0.1mm [0.004”] ) and then the factory shim can be reused, however,
quite often these measurements will vary slightly between one factory
differential and the next.
If this is the case you must create a new shim pack thickness by using
the measurements you recorded earlier to find a desired measurement
for ‘D’ in Figure 7.
Use the following calculation:
A + B – C = D (Replacement Shim Pack)
HINT : If your calculations are correct then the following
calculation will also be true:
A + B – C – D = ZERO

Create a shim pack to match the thickness calculated as ‘D’.
To achieve the desired shim thickness you can:
•Machine down the factory shim thickness.
•Add shims between the factory shim and the bearing cup.
HINT : A selection of shims of this size have been supplied
with your Air Lockerkit.
•Purchase new factory shims at the desired thickness.
•Use a universal shim kit available from most drive train
specialists.
•Add small amounts of shim between the bearing cone and the
bearing seat.
NOTE : NEVER machine the Air Locker.

3 Installing the Air Locker
14
3.3 A B Mounting the Ring Gear

Apply a thin film of high pressure grease to the ring gear shoulder
of the Air Locker to prevent seizing.

Thoroughly clean any thread locking compound or other foreign
matter from the holes of the ring gear, the threads of the ring gear
bolts, and the mating surfaces between the ring gear and the Air
Locker flange.
HINT : Stoning the ring gear mounting face before
installation will remove any high spots around the
threads.

Heat the ring gear to between 80 and 100°C [175 - 212°F] in hot
water or in an oven to slightly expand the gear and facilitate
assembly.
NOTE : NEVER HEAT GEARS WITH A FLAME! This could
damage the hardened surface of the gear and result
in premature wear or failure.

Dry the gear and bolt holes with compressed air (if wet).

Install the ring gear onto the Air Locker by aligning the bolt holes
and then gently tapping it around in a circle with a soft mallet.
Avoid using the bolts to pull down the ring gear as this puts excess
strain on the bolts and the differential flange.

Apply a thread locking compound to the thread of each ring gear
bolt before inserting it. Do not apply threading compound directly
into the threaded hole as this could prevent the bolt from reaching
its full depth.

Tighten the ring gear bolts in a star pattern with a torque wrench
according to your vehicle manufacturer’s specified torque.

3 Installing the Air Locker
15
3.4 A B Installing the Carrier Bearings

Apply a thin film of high pressure grease to both bearing journals of
the Air Locker.

Using a bearing press or arbor press, press one of the original
tapered roller bearing cones onto the bearing journal opposite to
the ring gear flange of the differential carrier (As shown in Figure 8.)
until the bearing seats firmly against the bearing journal shoulder.
Figure 8.

Invert the Air Locker and press the bearing cone which was
supplied with the Air Locker kit onto the bearing journal on the ring
gear flange side of the differential (the seal housing side) until the
bearing seats firmly against the bearing journal shoulder.
NOTE : Never re-use any bearings which are damaged or
worn. Do not add any shims between the seal
housing bearing and the bearing seat.

3 Installing the Air Locker
16
3.5 A B Preload Shim Measurement
In order to preload the tapered roller bearings in your Air Locker,
measurements need to be taken so that a value can be calculated for
the total shim thickness ‘E’ in Figure 9.
Figure 9.
3.5.1 A Front Access Housing Preload

Hold the bearing cups in place over their matching bearing cones.

Insert and hold the Air Locker into the differential housing.

Insert the shim pack determined earlier as ‘D’ between the bearing
cup (right hand side as shown in Fig.7.) and the differential
housing.

Push (or lightly pry) the Air Locker hard across to the right-hand
side, and measure the gap (also called the ‘end float’) between the
bearing cup and the housing with a feeler gauge.

Record this measurement.

3 Installing the Air Locker
17
3.5.2 B Clamshell Housing Preload

Assemble the shim pack determined earlier as ‘D’ (Fig.7.) into the
bearing bore of the deep half of the clamshell.

Using a bearing press or arbor press, press one of the original
bearing cups into the bottom of the same bearing bore (i.e., until it
stops against the shim pack).
HINT : You should not be able to rotate the shim pack
underneath the bearing cup if it has been pressed in
far enough.

With the deep half of the clamshell sitting firmly on a horizontal
surface, set the Air Locker into the bearing cup inside the clamshell.

Assemble the bearing cup supplied with the Air Locker kit onto the
bearing cone now positioned at the top of the Air Locker.

Put any remaining shims from the Air Locker shim kit (supplied)
together and measure the total thickness.

Set the shim pack on top of the bearing cup (i.e., the position of
shim pack ‘E’ in Fig.10.).

Carefully assemble the shallow half of the clamshell over the top of
the Air Locker.

Measure the preload gap that exists between the two halves of the
clamshell housing with a feeler gauge. (Refer to Fig.10.)
Figure 10.

3 Installing the Air Locker
18
NOTE : The preload gap should be the same when measured
all the way around the housing. If this is not true, then
reposition the shallow clamshell half and re-measure.

Subtract the amount measured at the preload gap from the
thickness of the shim pack placed on top of the bearing cup.

Record the result as this is your true ‘end float’ amount.
3.6 A B Calculation & Selection of Preload Shims

Consult your vehicle manufacturer’s service manual to determine
the carrier bearing preload amount specified for your vehicle.
NOTE : If your service manual specifies preload in terms of a
torque value measured off the drive pinion flange,
then assume a preload amount of 0.25mm [0.01”] for
the following calculations. Once you have assembled
the housing to check the final backlash (Refer to
Section 3.12 Checking the Backlash) you should verify
that your preload is correct using a torque wrench and
your service manual’s table of values.

Add the specified preload amount to the end float measurement
determined with the feeler gauge to determine a shim amount for
‘E’ (Refer to Figure 9.).
PRELOAD + END FLOAT = SHIM PACK

Create a shim pack ‘E’ to closely match the measured amount.
NOTE : When creating the shim pack ‘E’, use at least 0.75mm
[0.030”] of the Air Locker shim pack between the
factory shim and the bearing cup in order to prevent
the cage of the bearing from contacting the factory
shim.
To achieve this desired shim thickness you can:
•Machine down the factory shim thickness.
•Add shims between the factory shim and the bearing cup.
•Purchase new factory shims at the desired thickness.
•Use a universal shim kit available from most drive train specialists.
NOTE : Do not add shims between the bearing cone and the
bearing seat and NEVER machine the Air Locker.