Part 1
To assembleGeneral measures before assembly
^ Parts and housing should be thoroughly washed before assembly.
^ Check the parts for wear. Change damaged or defective parts.
^ If there was a lot of swarf in the gearbox, all bearings should be replaced. Always change both bearings on one shaft, even if only one is damaged.
^ Change seals at the drive shafts.
^ All bearings and friction surfaces must be oiled before assembly with the same type of oil as used in the gearbox. Refer to Summary of lubricants and sealants.
1. Mount the clutch housing on a service stand with 87 92 228 Holder, transmission.
2. Carefully scrape off the old sealant residue from the mating surface without damaging the sealing surfaces.
3. Fit the differential into the clutch housing and lubricate the bearing.
4. Mount the output shaft into its seat, lubricate the bearing and fit the bearing race. Put on the bearing support and tap it down. Use 87 92 202 Sleeve and 87 91 204 Sleeve, bearing race. Use 74 96 268 Thread locking adhesive to all bolts and fit them. Tighten the 3 bolts in the middle alternately.
Tightening torque 45 Nm (33 ft. lbs.)
The outer bolts should only be tightened to:
Tightening torque 24 Nm (18 ft. lbs.)
5. Fit the gear wheels of 1st and 2nd gear with synchromesh assembly on the output shaft using 87 92 103 Assembly fixture, 1. Then fit the assembled components on the output shaft. Fit the gear wheel of 3rd gear and a new spacer sleeve (paired with clamping sleeve) on the output shaft. Note that the used pinion must face the same way as before, i.e. with the machined groove up. Do not let the fitted gears go too far down the shaft, save 15 mm. Otherwise it is not possible to fit the input shaft.
6. Place the input shaft in the housing and lubricate the bearing. Fit a cable tie to keep the gears on the input and output shafts meshed.
7. Press down the gear on the output shaft on the face of the clutch housing. Carefully tap with a hammer, 87 91 204 Sleeve, bearing race and 87 90 867 Assembly ring, input shaft bearing until a new clamping sleeve (paired with spacer sleeve) and the 4th gear can be fitted. Turn the 4th gear with the machined groove down.
8. Fit 87 91 261 Puller, pinion and pull until the 4th gear pinions and gear wheels on the input and output shafts are flush with each other. Cut off the cable ties and remove 87 92 103 Assembly fixture, 1. Check that 1st and 2nd gear pinions run easily on the output shaft.
9. Lift the input shaft a little and fit the reverse gear wheel with pinion and synchromesh. The hole in the reverse shaft should be facing the channel in the clutch housing.
Important: If the oil hole is facing in the other direction, the reverse gear has been wrongly assembled. If this is the case, rectify the fault.
10. Fit the gear-changing mechanism and clutch housing. The forks should be in neutral position. Fit the preload washer.
11. Place the 1st-2nd and 3rd-4th forks in the synchromesh sleeves and turn and push the mechanism into position. The synchromesh sleeves should be in the neutral position. Insert the locating sleeves and align the screws.
12. Fit the reverse lever with the two remaining screws. Tighten the 3 screws.
Tightening torque 24 Nm (18 ft. lbs.)
Important: The oil plate on the selector fork for reverse gear should be fitted under the edge of the gear mechanism.
13. Fit the fork onto the reverse synchromesh sleeve. Make sure the reverse lever engages with the reverse fork groove. Then push in the shaft.
14. Engage reverse with the gear changing mechanism and make sure it is engaged properly.
15. Thoroughly clean the sealing surfaces with 30 02 599 Cleaning agent or the like. Apply a 2 mm string of 93 21 795 Flange sealant to the clutch housing's contact surface.
Important: Care must be taken when re-assembling the gearbox and applying flange sealant. If the sintered plug is replaced in the gearbox vent, oil in the gearbox can be expelled through the shaft seals.
16. Make sure the reverse shaft support is positioned correctly so that the screw can be fitted after mounting the gearcase.
17. Place the gearcase onto the clutch housing. The mark on the gear selector arm must be aligned with the mark on the gearcase. The shift arm must be in the position must be as illustrated (17A). When the gearcase is fitted to the clutch housing and the distance between them is approximately 25 mm, turn the shift arm clockwise so that its guide roller falls into the groove (17B).
18. First secure the clutch housing and gearcase slightly using two bolts. The tap up the guide sleeves. Loosely fir the rear axle bolt. If necessary, use a small screwdriver to guide the bolt hole towards the hole in the gearcase. Fit the remaining bolts. The three lower marked bolts should be replaced with quality 10.9.
Tightening torque 24 Nm (18 ft. lbs.)
Tightening torque, lower marked bolts (quality 10.9) 31 Nm (23 ft. lbs.)
19. Tighten the screw for the reverse shaft. Note the O-ring!
Tightening torque 24 Nm (18 ft. lbs.)
20. Tighten a new flange screw (quality 10.9) to the reverse shaft support. If there is already a 10.9 screw, it can be reused (Quality designation is stamped on the screw head).
Tightening torque, quality 8.8: 20 Nm + 120± (15 ft. lbs. +120±)
Tightening torque, quality 10.9: 20 Nm + 45± (15 ft. lbs. +45±)
21. Put the bearing onto the output shaft, lubricate the bearing and pull it with 87 91 261 Puller, pinion . Pull only until the collet makes contact.
22. Put the 5th gear wheel on the output shaft. Tap down the 5th gear wheel slightly with a hammer and 78 41 067 Sleeve, inner driver bearing. Fit 87 91 261 Puller, pinion. Then pull the gear wheel against the bearing with the puller and fit a new nut.
Important: Lubricate the threads and faces of the nut with gearbox oil.
23. Fit 87 91 428 Driver onto the input shaft. Place the tip of the dial indicator on the input shaft bearing. Fit the drilling machine to the tool and "run" the gearbox to settle the bearing. Operate the drilling machine while pressing first for about 20 revolutions and then zero the dial. Operate the drilling machine while lifting it for another 20 revolutions and take a reading (or until the reading has become stable). Measure the axial play, it should be 0.09-0.15 mm. (The play will go down to 0.04-0.11 mm when the output shaft bearing has been adjusted to the correct preload.) Adjust with shims under the bearing support as necessary.
^ Thicker shims = increase clearance
^ Thinner shims = decrease clearance
^ Shims are available in dimensions 0.10; 0.15; 0.30 mm.
Important: Tap carefully with a plastic hammer on the input shaft so that the bearing race by the 5th gear wheel is abut against the bearing support
24. When adjusting axial play on input shaft:
Undo and remove the 4 screws from the bearing support. Refit the bearing support together with the correct package of shims and tighten alternately.
Tightening torque 38 Nm (28 ft. lbs.)
Check play again. Remove the three tools.
25. Fit 87 92 772 Holding tool, input shaft B207) or 87 92 517 Holding tool, input shaft (D223L) to support the input shaft when the 5th gear synchromesh nub is tapped down.
26. Fit the 5th pinion with needle bearing. Lubricate the bearing.
27. Assemble the wire ring, the 3 leaf springs, the baulk ring and the hub with 87 92 582 Fixture, 5. Tap down the hub with 78 41 067 Sleeve, inner driver bearing onto the input shaft spline.
28. Remove 87 92 582 Fixture.
29. Fit the 5th synchromesh sleeve with the tip angles down.
The 6 stop lugs on the synchromesh sleeve must mesh with the 6 deep tooth gaps in the synchromesh hub.
30. Remove 87 92 772 Holding tool, input shaft .
31. Fit 87 92 194 Dial gauge kit against the gear wheel with 87 90 727 Bracket, dial clause. Engage 1st gear (see illustration) and press down the 5th gear synchromesh hub to "lock" the gearbox. Tighten the nut and measure alternately with the dial gauge until an axial play of 0.06 +0.05 mm is obtained on the output shaft. Use a short Me bolt in the sealing face as a break point. Disengage 1st and 5th gears.
Important: Do not break in directly below the gear teeth, insert properly.
32. Check and adjust the preload of the differential as follows:
Thread in the bearing race (not all the way in) and fit the bearing support without O-ring, shaft seal and shim. Tighten 4 screws.
Tightening torque 24 Nm (18 ft. lbs.)