ARB RD165 Air Operated Locking Differential Installation Guide

1 Introduction

IMPORTANT: Before dismantling your vehicle, read this guide and your vehicle manufacturer's service manual thoroughly.

1.1 Pre-Installation Preparation

This booklet supplements your vehicle manufacturer's service manual. ARB updates guides regularly, but discrepancies may occur. Always follow your service manual in case of conflict. ARB recommends professional installation by trained distributors.

Ensure your Air Locker kit is correct for your vehicle and contains all listed parts. Have necessary tools, parts, and materials ready. Allow adequate vehicle downtime.

HINT: Mark completed steps with a checkmark (✓) to avoid missing any.

1.2 Tool-Kit Recommendations

1.2.1 Tools

• Standard automotive sockets, wrenches, Allen keys, drills.
• Dial indicator or measuring tool for ring & pinion backlash.
• Automotive feeler gauge.
• Razor knife for nylon tubing.
• Differential housing spreader (e.g., ARB #0770003).
• Torque wrench (refer to vehicle service manual).
• Lubricant drain reservoir.
• Measuring tools for pre-load and backlash shimming.
• 11.2mm [7/16"] drill and ½” NPT tap.
• Automotive bearing puller (e.g., ARB #0770001) or differential carrier bearing puller.
• Bearing press or arbor press.

1.2.2 Supplies

• Thread lubricant/sealant (e.g., LOCTITE #567).
• Thread locking compound (e.g., LOCTITE #272).
• Differential cover gasket or sealant.
• Sufficient differential oil for refilling.
• Soap and water mixture for leak testing.

2 Removing the Existing Differential

2.1 Vehicle Support

Securely support the vehicle on a hoist, preferably a chassis hoist, for convenient access and to allow axle rotation. Release the parking brake and leave the vehicle in neutral. Chock wheels if necessary.

2.2 Differential Fluid Drain

HINT: Check oil for metal particles, which may indicate worn bearings or components.

• Clean around the differential cover plate seal.
• Position a drain reservoir and loosen cover bolts.
• If a drain plug exists, remove it to drain oil.
• If no drain plug, loosen cover bolts and pry the cover slightly to drain oil.
• HINT: Consider drilling and tapping for a drain plug for future oil changes.
• Remove the differential cover plate.

2.3 Disconnecting the Axles

IMPORTANT: Ensure axle assembly is concentric and straight before installation, as misalignment can cause wear or failure. Collision damage or heavy off-road use may affect axle straightness.

• Remove wheels and brakes per vehicle manual.
• Remove axle shafts per vehicle manual.
• NOTE: Axle oil seals are delicate; support axle shafts when removing to prevent damage.

2.4 Marking the Bearing Caps

Use a center punch to mark bearing caps and housing to identify their original positions (e.g., 'LEFT', 'RIGHT', 'UP', 'DOWN').

HINT: A common method is one punch mark for the left side and two for the right side, applied to both the cap and housing.

Figure 1. shows the process of marking bearing caps.

2.5 Checking the Current Backlash Amount

IMPORTANT: Some aftermarket gear sets may have different backlash requirements than specified by the vehicle manufacturer. Compare measurements to your service manual. Deviations may be necessary for quiet running.

• Refer to your vehicle service manual or authorized ARB installer for details.
• Set a depth indicator on a ring gear tooth (Figure 2.).
• Support the pinion gear and rotate the differential to measure backlash (maximum variation).
• Rotate the differential 90° and measure again for accuracy.
• Record the average of all measurements.

2.6 Removing the Differential Center

IMPORTANT: Spreading the housing is critical for setting bearing pre-load. Improper pre-load causes bearing wear, increased stress, noise, and gear damage.

• Remove both bearing caps.
• Carefully spread the housing (Figure 3.) to remove the differential center (refer to vehicle service manual).
• NOTE: Do not spread the housing more than 0.50mm [0.020”].
• HINT: Do not mix up left and right bearing cups.
• Pull the differential carrier forward to remove it.
• NOTE: The differential center is heavy; handle with care to avoid dropping.
• Relieve spreader tension immediately after removal.

3 Installing the Air Locker

3.1 Insuring Adequate Oil Drainage

IMPORTANT: Some Salisbury axles have poor oil drainage, leading to axle tubes filling with oil, blocked air vents, and oil expulsion. If no lower drainage point exists, modify the housing.

• Inspect the differential housing for adequate drainage in both axle tubes (Figure 4.).
• If no drainage slot is present on the left side, create one for the seal housing tube clearance (Refer to Section 3.8).
• If drainage is inadequate, cut a slot or hole on the lower side of the tube(s) to allow oil to drain.
• NOTE: Ensure all grinding dust and chips are cleaned from the housing. Check axle air vents are clear.

3.2 Approximate Backlash Shimming

Measurements are needed to calculate shim thickness for pre-load and backlash.

• Secure the original differential to a workbench.
• Remove ring gear bolts.
• Tap the ring gear off the carrier using a plastic or copper hammer.

Figure 5. illustrates the original differential components.

• Assemble the original bearing cup onto the right-hand side cone of the original differential carrier.
• Using a caliper, measure the distance 'A' from the bearing cup shoulder to the ring gear mounting face (Figure 5.). Record this measurement.
• NOTE: Use the bearing cup that originally came off the right-hand side.
• Remove bearings from the original carrier using a bearing puller (ARB #0770001). Inspect and replace if necessary.
• Apply high-pressure grease to the Air Locker bearing journals.
• Using a bearing press, press one bearing cone onto an Air Locker bearing journal until seated (Figure 6.).
• NOTE: Do not add shims between bearings and the OE carrier seat.
• Invert the Air Locker and press the other bearing cone onto the opposite journal until seated.
• Assemble the new bearing cup onto the right-hand side of the Air Locker and measure the total distance 'C' (Figure 7.).
• NOTE: Shim pack 'B' will be determined later.
• The shim pack 'B' thickness should make distance 'C' on the Air Locker match distance 'A' on the original differential (within 0.1mm [0.004”]).
• Calculate 'B' using: A - C = B (Replacement Shim Pack).
• HINT: If calculations are correct, A - B - C = ZERO.
• Select shims from the kit to make thickness 'B'.
• NOTE: If necessary, shim kit 'B' can be made from standard Dana shims and placed between the bearing cone and seat.
• Place shim pack 'B' on the bearing cup.
• Re-measure distance 'C' (including shim pack 'B') to ensure it matches 'A'.
• NOTE: NEVER machine the Air Locker.

3.3 Mounting the Ring Gear

• Apply high-pressure grease to the ring gear shoulder of the Air Locker.
• Clean ring gear holes, bolt threads, and mating surfaces.
• HINT: Stoning the ring gear mounting face can remove high spots.
• Heat the ring gear to 80-100°C [175-212°F] in hot water or an oven.
• NOTE: NEVER HEAT GEARS WITH A FLAME.
• Dry gear and bolt holes with compressed air.
• Align bolt holes and gently tap the ring gear onto the Air Locker with a soft mallet. Avoid using bolts to pull the gear down.
• Apply thread locking compound to each ring gear bolt thread.
• Tighten ring gear bolts in a star pattern with a torque wrench to the vehicle manufacturer's specification.

3.4 Drilling and Tapping the Bulkhead Port

An airline port must be drilled and tapped into the differential housing.

NOTE: Higher ratio gearing uses thicker ring gears. Ensure the hole location is far enough from the ring gear teeth.

• Mark a position on the outside of the differential housing (Figure 8.). Choose a location for maximum clearance. The bulkhead position must allow clearance for the seal housing tube.
• Cover the drive pinion and axle tube areas with a rag.
• Drill the hole using an 11.2mm [7/16”] drill.
• Tap the hole using a ¼” NPT pipe tap.
• Remove any sharp edges from the hole.
• Carefully remove rags and inspect for metal filings.

3.5 Assembling the Seal Housing

• Ensure seal housing grooves and airway are clean and free of contaminants.
• Inspect seal housing O-rings for damage.
• Lubricate O-rings with oil and insert into seal housing grooves.
• NOTE: Ensure O-rings are not twisted when seated.
• Lubricate the seal housing running surface on the Air Locker carrier with oil.
• Assemble a bearing cup onto the left-hand side of the Air Locker.
• Slide the seal housing onto the bearing journal with a gentle twisting motion.
• IMPORTANT: A 4mm Master Shim (382A) is for the “thin” bearing cup; do not use with the “thick” bearing cup (382-S).

3.6 Pre-Load Shimming

Measurements are needed to calculate shim thickness 'D'.

• Insert the Air Locker into the differential housing.
• Insert shim pack 'B' between the bearing cup (right-hand side) and the axle housing.
• Push the Air Locker across to the right-hand side and measure the maximum gap ('end float') between the seal housing and axle housing with a feeler gauge (Figure 10.).
• Consult your vehicle manufacturer's service manual for carrier bearing pre-load specifications.
• Add the specified pre-load to the end float measurement to determine shim amount 'D'.
• PRE-LOAD + END FLOAT = SHIM PACK
• Create shim pack 'D' from the supplied shims.
• NOTE: The shim kit contains various shims for Dana 60 applications.
• Remove the Air Locker.
• Install shim pack 'D' between the bearing cup and seal housing (Figure 9.).
• Spread the differential housing again (Refer to Section 2.6).
• Re-install the Air Locker into the axle housing.
• NOTE: If the Air Locker is tight, increase spreader tension, but do not exceed 0.50mm [0.020”].
• NOTE: Use ARB Shim Driver #0770004 for installing shims.
• Rotate the seal housing until the tube points straight out.
• Release all spreader tension.
• Check for backlash between ring and pinion gears. No backlash indicates incorrect shim thickness.

3.7 Reinstalling the Bearing Caps

• Install bearing caps oriented as marked during removal. Tighten bearing cap bolts, but not to final torque yet.
• Check for clearance between the bearing cap and seal housing tube. If insufficient, remove the cap and re-bend the tube.
• Tighten all bearing cap bolts with a torque wrench to the vehicle manufacturer's specification.

3.8 Checking the Backlash

• Set a depth indicator on a ring gear tooth (Figure 11.).
• Support the pinion gear and rotate the differential to measure backlash.
• Rotate the differential center 90° and measure again for accuracy.
• Refer to your vehicle service manual for specified backlash limits. If outside limits, remove and re-shim.

3.8.1 Re-Shimming the Backlash

NOTE: This step is only for adjusting incorrect backlash.

• Remove bearing caps.
• Remove the differential.
• To decrease backlash, reduce shim thickness 'B' and increase shim thickness 'D' by the same amount. Reverse to increase backlash.
• Remount the differential.
• Release spreader tension.
• Check backlash again.

3.9 Setting Up the Bulkhead Fitting

• Apply thread sealant to the outside threads of the bulkhead body.
• Screw the bulkhead body into the tapped hole and tighten with a 14mm [9/16”] spanner.
• Wipe the area clean of excess thread sealant.
• Bend the seal housing tube to shape (Figure 12.) and trim to length.
• Insert the tube end into the bulkhead fitting until it protrudes approximately 8mm [5/16”].
• Assemble a small O-ring over the protruding tube end.
• Install the brass spacer.
• Install the second small O-ring after the spacer.
• Hold the seal housing tube in the fitting and insert the chamfered end of the center compression nut over the tube. Screw it into the bulkhead body and tighten with a Pozidriv #3 screwdriver.
• NOTE: Ensure the seal housing tube is fully inserted into the center compression nut during tightening.
• NOTE: Firmly tighten the center compression nut to form a good seal.

3.10 Profiling the Seal Housing Tube

• Completely remove the differential spreader.
• Gently bend the seal housing tube to run along the inside of the differential housing (Figure 14.). Use hands or soft tools.
• NOTE: Keep the tube away from bearing caps or casting to prevent wear from vibration or shock.

3.11 Bench Testing the Air Locker

• Apply 620kPa [90 PSI] shop air to the seal housing tube; the Air Locker should engage.
• Check all fittings and the seal housing for air leaks.
• Rotate the differential carrier by turning the pinion flange while applying air pressure.
• NOTE: For accurate leak testing, use a shut-off valve and pressure gauge (ARB #0770005). Close the valve at 620 kPa [90 PSI], disconnect the air hose, and check for pressure drops (Figure 15.).
• If leaks are found, spray a soap and water mixture onto air fittings. Bubbles indicate leaks.
• NOTE: Do not spray soapy mixture inside the differential.
• Check that leaky fittings are tightened. Disassemble, clean threads, and reapply sealant if leaks persist.
• If leaks are found at the seal housing, remove the assembly and examine O-rings for defects, damage, or foreign material. Replace if necessary.

4 Installing the Air System

4.1 Mounting the Solenoid

4.1.1 Connection to an ARB Air Compressor

• Remove one 1/8" BSP plug from the compressor tank port.
• Apply Teflon paste to the 1/8" BSP nipple on the solenoid and insert into the port. Rotate the solenoid to avoid obstructing other ports.
• NOTE: The solenoid coil and stem can be removed for easier installation.
• NOTE: Solenoids are marked with #1 ports. If space is limited, a second solenoid can be daisy-chained by removing the plug from a redundant #1 port and connecting the second solenoid's nipple.
• NOTE: The solenoid exhausts air through the center of the black retaining cap when the Air Locker is disengaged. Ensure this orifice is not obstructed.
• Assemble the 6mm push-in fitting into the solenoid outlet port (stamped "2") and hand tighten.

Figure 16. shows the solenoid connections and a daisy-chained configuration.

4.1.2 Connection to an Alternate Air Source

ARB recommends a genuine ARB Air Compressor for quality and dependability, but the Air Locker system can use other air sources meeting these guidelines:

• Minimum supply of 85PSI [586kPa].
• Air source must have sufficient tank capacity to actuate the Air Locker(s) without hesitation.
• HINT: Ensure capacity by engaging, disengaging, and re-engaging the Air Locker without the source needing to regenerate.
• Supply clean air, free of rust, dirt, and water.
• Match the 1/8" BSP porting of the Air Locker solenoid.
• Mount solenoid near the air supply, secured from vibration and shock.
• Connect air supply to the 1/8" BSP inlet port (stamped "1") using thread sealant.

IMPORTANT: ARB does not warrant Air Lockers against damage from alternate air supplies. Consult your ARB distributor if unsure.

4.2 Running and Securing the Air Line

Plan the air line path carefully, considering vehicle and air source position.

• Account for axle travel when running the line from the axle. Leave slack for suspension travel.
• Avoid leaving air lines hanging loosely where they can snag.
• HINT: Cable tying the air line to a flexible brake line helps manage axle travel and prevent snagging.
• Run the air line fully before trimming to avoid complications.
• Ensure the line does not contact sharp or abrasive surfaces.
• Avoid tight bends that could kink the line and restrict airflow.
• Keep the air line away from exhaust components.
• Do not use excessive air line length, as it can increase compressor tank drain.
• Support the air line with cable ties where possible.
• Trim the air line with a sharp knife at the solenoid end to avoid distorting the tube for the push-in fitting.
• NOTE: To remove the air line from a push-in fitting, push the line in, press the flange inward, and pull the line out.

4.3 Connection to the Bulkhead Fitting

• If the axle assembly is removed or for IFS, remount to position the bulkhead fitting correctly for air line access.
• Trim air line to length with a sharp knife.
• Assemble an aluminum washer onto the banjo bolt, insert through the banjo fitting, assemble a second aluminum washer, and tighten into the bulkhead fitting with a 14mm [9/16”] spanner (Figure 17.).
• Apply thread sealant to the tapered thread of the compression fitting body and screw into the banjo fitting. Tighten with a 12mm spanner.
• Insert the outer compression nut and ferrule over the air line. Orient the ferrule as shown in Figure 17.
• Push the airline into the compression fitting body and screw the outer nut down onto it. Tighten with a 12mm spanner.
• NOTE: Some force is needed to crush the ferrule; the nut tightens against a stop. Over-tightening does not improve the seal.
• Secure any loose tube sections with a cable tie.
• NOTE: For straight routing, screw the compression fitting body directly into the bulkhead fitting body (Figure 17.).

5 Mounting & Connecting the Electrical System

5.1 Mounting the Actuator Switch(es)

Air Locker actuator switches can be panel mounted in a 21mm x 36.5mm [0.83" x 1.44"] rectangular cutout.

NOTE: Attach the cover plate only after the switch is mounted and wired.

Mount switches in a location convenient and safe for the operator:

• Switches must be securely mounted, not dangling.
• Switches should be within easy reach and operable without distraction.
• Switches should be visible to the driver for status indication ('ON'/'OFF').
• Mounting position should minimize accidental operation.
• Ensure at least 50mm [2"] clearance behind the cutout.
• Avoid mounting switches where they could be exposed to water.
• ARB recommends applying the Air Locker Warning Sticker near the switch.
• NOTE: If no suitable dashboard position is found, a surface-mounted bracket (Figure 18.) is available from ARB distributors.

5.2 Wiring the Actuator System

5.2.1 Connection to an ARB AIR COMPRESSOR

Wiring the Air Locker switches and solenoids to an ARB Air Compressor can be done directly using the supplied wiring loom (Figure 19.).

NOTE: Figure 19. shows the 180409 model loom. Refer to your ARB Air Compressor Installation Guide for configuration details.

Figure 20. shows switch terminal identification.

5.2.2 Connection to an Alternate Air Source

Wire switches according to Figures 21. and 22., depending on whether one or two Air Lockers are installed.

5.2.2.1 Single Air Locker System

• If only one Air Locker is installed, wire the switch and solenoid per Figure 21., regardless of front or rear axle installation.
• Attach the appropriate switch cover ('FRONT' or 'REAR') to the switch.
• NOTE: Refer to Figure 20. for switch terminal identification and orientation.

5.2.2.2 Dual Air Locker System

• If two Air Lockers are installed, wire switches and solenoids per Figure 22. This configuration allows SOLENOID 2 actuation only if SOLENOID 1 is already on.
• Attach the "REAR AIR LOCKER" switch cover to SWITCH 1 and the "FRONT AIR LOCKER" switch cover to SWITCH 2.
• NOTE: Refer to Figure 20. for switch terminal identification and orientation.
• Configure SOLENOID 1 for the rear axle Air Locker and SOLENOID 2 for the front axle Air Locker.

6 Testing & Final Assembly

6.1 Leak Testing

• With the vehicle parked and engine off, charge the air system fully.
• NOTE: With the Air Locker disengaged, the air source should not recharge over time. Intermittent recharging usually indicates a leak at solenoid fittings or the compressor tank O-ring.
• Actuate the Air Locker(s).
• The compressor should not recharge for at least 15 minutes. Recharging sooner indicates a leak.
• NOTE: For alternate air sources, leak test with a pressure gauge and shut-off valve before solenoid input.
• If leaks are found, spray a soap and water mixture onto all air fittings while the system is charged. Bubbles will indicate leaks.
• Check that leaky fittings are tightened. Disassemble, clean threads, and reapply sealant if leaks persist.

6.2 Reinstalling the Axles

• Insert both axles fully into the housing and tap them inward.
• NOTE: Be careful not to damage axle oil seals with the axle spline.
• Reconnect the drive shaft to the differential drive flange.
• Reassemble the differential assembly components (hubs, brakes, wheels, etc.) per your vehicle's service manual.

6.3 Testing the Air Locker Actuation

Verify air system, electrical system, and Air Locker function:

• Support the vehicle so wheels can rotate freely (e.g., on axle stands).
• Ensure parking brake is off, transmission is in neutral, and Air Locker switch is 'OFF'. The switch's illuminated symbol should be 'OFF'.
• Turn ignition to 'ON'.
• Charge the air supply to maximum pressure.
• Support the drive shaft flange and rotate one wheel by hand. The opposite wheel should turn without resistance.
• Turn the Air Locker switch to 'ON'. The illuminated symbol should light up.
• Rotate the same wheel again; both wheels should rotate together.
• Turn the switch 'OFF'.
• Rotate the same wheel; wheels should rotate in opposite directions again.

6.4 Re-Sealing & Filling the Differential

NOTE: Consult the ARB Air Locker Operating & Service Manual for differential lubricant specifications.

• Replace the differential cover using gasket sealant or a new gasket.
• Refill the differential with oil to the filler hole level.
• Rotate the differential center 2 full turns.
• Check and adjust oil level if necessary.
• Replace filler plug, applying thread sealant if it's a threaded type.
• Wipe the differential housing clean of oil or grease.

6.5 Post-Installation Check List

Complete this checklist to ensure all vital steps were performed:

• Air system leak tested.
• Thread locking compound used on ring gear bolts.
• All torque settings comply with vehicle manufacturer's specs and were set accurately.
• Differential fluid complies with ARB recommendations and is filled correctly.
• Air lines and wiring securely cable tied.
• Switches securely mounted within reach, away from accidental engagement.
• Switches function properly and illuminate when Air Locker(s) are engaged.
• All operators have read and understand the ARB Air Locker Operating & Service Manual.
• Air Locker Warning Sticker located near the actuator switch(es).

INSTALLATION PERFORMED BY: _________________________

DATE OF INSTALLATION: _________________________

ODOMETER READING: _________________________

ARB AIR LOCKER SERIAL No: _________________________

7 Parts List

RD165 Dana 60, 32 SPL, 4.10 & DN

7.1 Exploded Assembly Diagram

(See itemized parts list overleaf)

Figure 23. shows the exploded assembly diagram.

7.2 Specifications

• Axle Spline: 32 tooth, Ø35.8mm [1.41"]
• Ratio Supported: 4.56:1 & up
• Ring Gear ID: 162.0mm [6.38"]
• Ring Gear OD: 248mm [9.75"]
• Ring Gear Bolts: 12 bolts on Ø191mm [7.50"]
• Ring Gear Torque: 149Nm [110 ft-lb]
• Backlash: 0.15-0.25mm [0.006-0.010"]
• Bearing Cap Torque: 108Nm [80 ft-lb]

7.3 Itemized Parts List

(See exploded diagram figure 23.)

NOTES

• 1: For replacement O-rings use only BS140 Viton 75.
• 2: For replacement bearing use Timken part # 387A / 382S.
• 3: Available only as complete 6 gear set # 728K101.
• 4: Use 150331 (4.0mm thick) for diff with thin bearing cup.
• 5: Available only as complete thrust washer kit 730K01.
• 6: Identify the spring type in your diff and order the correct diff case to replace. Replace the spring and/or the corresponding clutch gear with the same type. (If spring type is changed, a matching diff case must also be used. See item 19.)
• 7: All diffs produced before serial #17070001 came with 5mm air connection system.
• 8: For information contact ARB.
• *: Not illustrated in exploded view.
• For ratios of 4.56:1 and up refer to RD164 (Section 2.164).

Part No. 2102165

Revision 27/10/2020

Copyright © 2015 by ARB Corporation Limited