Part 2
TRANSFER CASE OVERHAUL - Part 2NOTE: Before commencing the overhaul procedure thoroughly clean the exterior of the transfer case. If the gearbox oil has not previously been drained, drain the oil into a suitable container.
Selector Fork, Dismantle and Inspection
1. Remove the retaining clip and separate the fork from the arm.
2. Detach the two nylon inserts from the selector fork feet and discard.
3. Thoroughly clean all components.
4. Examine the fork, arm and pivot pin for wear. Renew as necessary.
5. Remove the O-ring and discard. Examine the shaft and lever for wear and damage, renew as necessary.
6. Examine the selector sleeve teeth and internal splines for damage and wear. Renew as necessary.
Selector Fork, Assemble
7. Fit new nylon inserts to the fork.
8. Assemble the fork to the selector arm and secure in position using a new retaining clip.
9. Lightly lubricate and fit the spring and selector plunger.
10. While compressing the plunger and spring, fit the selector fork, operating arm assembly and selector sleeve simultaneously.
11. Select neutral gear position at the operating arm.
12. Fit a new O-ring to the selector lever shaft. Lubricate the O-ring and fit the lever assembly to the rear cover, noting that when fully assembled the lever should lie parallel with the joint face of the rear cover.
13. Fit a new retaining clip to secure the selector fork operating arm to the selector lever shaft.
14. Remove any previous sealant from the Torx screw. Align the selector lever shaft groove to the retaining screw hole, apply a small amount of Loctite(r) 242 to the screw threads and using Torx 25 bit tighten the screw to 7-9 Nm (5-7 ft lb). Ensure that the screw locates in the groove of the shaft.
15. Clean any previous sealant from the Torx screw. Apply a small amount of Loctite(r) 242 to the threads of the screw and fit to the selector fork operating arm. Tighten using Torx 25 bit to 7-9 Nm (5-7 ft lb).
Bearing Carrier, Dismantle, Inspection And Assemble
1. Remove the circlip and drive or press the transfer shaft from the bearing.
2. Remove the circlip retaining the bearing in the carrier.
3. Drive or press the bearing from the carrier and discard the bearing.
4. Clean and examine the carrier for cracks and general condition. Renew as necessary.
5. Press or drive a new bearing into the carrier and secure with the circlip.
Transfer Shaft, Inspection And Assemble
1. Clean the transfer shaft.
2. Visually examine the external splines for damage and wear, if worn fit a new the component.
3. Check the phosphor bronze bush for wear by measuring the internal diameter of the bush with internal calipers and a micrometer or with an internal micrometer. The bush diameter must not exceed 38.515 mm (1.516 in), fit a new transfer shaft if the bush has worn above the figure given
4. Drive or press the transfer shaft into the bearing in the carrier. Secure the shaft with the circlip.
5. Fit the carrier to the rear cover, fit the anti rotation dowel and secure the assembly with the snap ring, noting that the open ends of the snap ring must be positioned by the cast relief in the bearing carrier upper face.
Transfer Sprocket, Inspection
1. Examine the sprocket teeth and splines for wear and damage, if either are evident discard the sprocket, otherwise clean and place to one side.
Chain, Inspection
NOTE: A stretched chain can be identified by either excessive noise when the gearbox is operational or by witness marks on the inside edges of the case. If either is evident, renew the chain.
1. Using a suitable solvent thoroughly clean the chain.
2. Check the chain links for wear and damage, if necessary renew the chain.
3. Place the chain to one side.
Center Differential And Sprocket, Dismantle And Inspection
1. Place the differential unit in a vice fitted with soft jaws. If the original components are to be refitted mark an identification line on the sprocket and differential unit.
2. Remove the bolts securing the sprocket to the differential.
3. Lift the differential assembly from the sprocket.
4. Examine the sprocket teeth for wear and damage, if either are evident renew the sprocket. Place the sprocket aside until the differential is ready to be assembled.
Center Differential, Dismantle And Inspection
1. Using a two legged puller, remove the bearings from the differential assembly and discard the bearings.
2. Secure the front half of the differential unit in a vice fitted with soft jaws. Remove the eight retaining bolts securing the front and rear halves of the assembly together, lift off the rear part of the differential unit. Note the identification marks on the exterior of the differential unit.
3. Remove the rear upper bevel gear and thrust washer.
4. Remove the pinion gears and dished washers along with the cross shaft.
5. Remove the front lower bevel gear and thrust washer from the front half of the differential unit.
6. Remove the front half of the differential unit from the vice and clean all components. Examine for wear or damage, renew if necessary.
Differential Pinions, Rolling Resistance
7. Using soft jaws secure the front half of the differential unit in the vice.
8. Fit the front bevel gear without the thrust washer. Lightly lubricate and fit the cross shaft, pinion gears and new dished washers.
9. Fit the rear bevel gear together with the thinnest thrust washer to the rear half of the differential. Assemble both halves of the differential noting the identification marks. Fit the bolts and tighten to 36-41 Nm (27-30 ft lb).
10. Invert the differential unit in the vice, fit the front output housing to the differential, locating the viscous unit splines on the front bevel gear. Fit the drive flange to the viscous unit and place the brake drum on top of the drive flange, secure with the nut. Check that the gears are free to rotate.
11. Tie a length of string around the brake drum, attach a spring balance to the free end and carefully pull the scale until a turning value is achieved. Alternatively use a torque wrench applied to the drive flange nut. Rotate the brake drum slowly by hand to overcome the initial load when using either method.
NOTE: Gears that have been run will rotate smoothly and will require a torque of 0.56 Nm (5 in lb), or the equivalent force using a spring balance 0.45 kg (1 lb). New gears will rotate with a notchy feel and will require a torque of not more than 2.26 Nm (20 in lb), or the equivalent force using a spring balance of 7.72 Kg (3.8 lb). Keep all components lubricated when carrying out these adjustments.
12. Change the thrust washer for a thicker one if the torque reading is too low and re-check the torque. Five thrust washers are available in 0.10 mm steps ranging from 1.05 to 1.45 mm.
13. Dismantle the unit when the rear bevel gear thrust washer has been selected.
14. Remove and retain the rear bevel gear and-thrust washer combination.
15. Repeat the procedure to obtain the correct thrust washer for the front bevel gear. It is not necessary to fit the rear bevel gear when checking the front bevel gear rolling resistance.
16. When the thrust washer has been selected for the front bevel gear. again dismantle the differential unit and set aside the thrust washer and front bevel gear combination.
Center Differential, Assemble
17. Fit the thrust washer and front bevel gear into the front half of the differential unit.
18. Fit the pinion gears with dished washers to the cross shaft and fit the assembly to the differential unit.
19. Fit the thrust washer and rear bevel gear to the rear half of the differential unit.
20. Align both halves of the differential noting the identification marks. Secure both halves together with the eight bolts. Tighten the bolts to 36-41 Nm (27-30 ft lb).
21. Check the overall torque required to turn the differential, this should be approximately equal to both bevel gears added together.
22. Drive or press new bearings onto the differential, noting that the smaller of the two bearings is fitted to the rear half of the differential.
Center Differential Sprocket, Assemble
1. Fit the sprocket to the differential noting that the face of the sprocket with the relieved threads must contact the flange of the differential housing. Observe the previously marked identification lines if the original components are being refitted.
2. Fit new bolts and tighten evenly to 41-61 Nm (30-45 ft lb).
Transfer sprocket, center differential assembly and chain, Assemble
1. Place the differential assembly and transfer sprocket inside the chain. If the original components are being refitted observe the identification marks previously applied to the chain and transfer sprocket. Fit the complete assembly simultaneously.
2. Carefully tap the differential bearing into its bore while easing the transfer sprocket onto the transfer shaft.
3. Ensuring that the transfer sprocket is fully seated, secure the sprocket to the transfer shaft with the circlip.
Front And Rear Cover, Main Casing, Assemble
1. Ensuring - that the joint faces of the front and rear covers are clean, apply a bead of Dow Corning 732 or a suitable equivalent silicone sealant to the joint face of the rear cover and evenly spread the sealant over the face. Do not over apply the sealant.
2. Fit the front cover, secure with the eleven bolts and one stud bolt, and tighten evenly to 30-49 Nm (22-36 ft lb). Do not wipe away the surplus sealant which is forced out of the joint.