AG 155/200 Dana Front axle – Reassembling the differential lock



Assemble the friction washer (5) on the mobile coupler (40). Slide the assembly into piston (4). Fit tab washer (2) and position snap ring (1) in the groove of the mobile coupler. In the housing without its seals, fit the piston (4) with the mobile coupler (40). The pin (7) is force fitted into the piston. Check that both the piston and pin slide freely in the housing. Once this check has been carried out, remove the piston and mobile coupler.
Fit new O’rings (3) (8). Position the piston with the mobile coupler then insert it by hitting around its rim with a plastic hammer.
Position spring (6) and washer (9), with the shoulder of the washer facing the spring. Place the assembly under tension using tool until washer (10) slides freely in the groove of the housing. Carefully loosen the tool so that the spring does not escape. Insert cone (13), if disassembled, on half-housing (26) using a press or appropriate fixture.


Insert the other cone (13), if disassembled, in cover (15).
Assemble half-housing (16) in cover (15) (with coupler teeth) with regard to the marks made during disassembly. Position washer (25) on sun gear (21), place the assembly in half-housing (16), while locating the washer tab in one of the holes on the half-housing.
Place the four planetary gears (17) and four spherical washers (18) on the two pins (19) then place the assemblies in half-housing (16) inserting the washer (18) tabs into the holes on the half-housing (16).


Place the other washer (25) on the other sun gear (21). Fit the assembly in half-housing (26) while respecting the position of the washer (25) tab.
Position half-housing assembly (26) on half-housing (16) with regard to the marks made during disassembly.
Join together half-housings (16) (26) and cover (15). Fit bolts (14) previously lightly smeared with Loctite 270. Tighten to a torque of 82 - 90 Nm. Position crownwheel (27) on half-housing (26). Smear bolts (20) with Loctite 270 and tighten to a torque of 140 - 155 Nm. Position cups (12) on their cones (13).
Place shim(s) (11) on washer (10).


Place the crownwheel assembly in housing (35). Check for the presence of centring bushes (43). Position the half-bearings (41). Moderately tighten bolts (42) so that cups (12) can move freely. Place the housing horizontally in a vice fitted with soft jaws, the crownwheel facing upwards.
Place a depth gauge. Tighten nut (24) and turn the crownwheel several times while pushing down vigorously on it in order to correctly seat the bearing cones in their cups. Retighten the nut in order to remove axial clearance.


Tighten nut (24) by three additional notches to obtain the correct preload value. Check the clearance between the teeth of the crownwheel and drive pinion using a dial gauge. Take three measurements at equidistant points. Calculate the average of the three measurements, to obtain a clearance of 0.18 mm - 0.23 mm. If the value is too high, reduce the thickness of shim(s) (11); if the value is too low, increase the shim thickness until the correct clearance is obtained.


Remove one by one bolts (42) and smear them with Loctite 270 then definitively tighten them to a torque of 115 - 127 Nm.
Refit lock washer (23) on bolt (22) previously lightly smeared with Loctite 270 and tighten to a torque of 16 - 25 Nm. Lock nut (24) by bending the tab into its corresponding slot.

Piston leak test

Fit a pressure gauge fitted with an airtight valve on to the supply side union of the differential lock. Feed compressed air at approximately 5 bar into the circuit and check for the movement of piston (4). Bring the pressure down to 0.3 bar and close the valve. No drop in pressure should be noted on the pressure gauge for approximately 1 minute. Remove the pressure gauge and valve.

Refitting swivel housings, wheel hub and drive shafts

Clean and inspect the components. Replace any parts found to be defective.
Check for the presence of bushes (47) on the axle housing.
Smear the mating face of the differential housing with the axle with a sealing compound such as Loctite 510 or its equivalent, and screw in two diametrically opposed guide studs. Refit the housing assembly (35).


Take out the guide studs. Fit and tighten bolts (1):
- AG 155H front axles: 125 - 140 Nm.
- AG 200H front axles: 215 - 235 Nm
Refit the swivel housings, wheel hubs and drive shafts. Refit the steering ram. Smear the bolts with Loctite 270 and tighten to a torque of 180 - 200 Nm.

Assembling front axle / frame

Couple the axle and its bearings to the front frame.
Top-up the oil level in the front axle housing oil level and then check the levels in the drive units. Carry out a road test of the front axle and the differential lock control. Check the oil tightness:
- of the seals and differential housing mating face,
- of the hydraulic unions.