Vehicles after change point in 1982 REPLACING BOTH BEARINGS FOR DIFFERENTIAL CASE - Final Drive Removed - Remove final drive - see 33 10 010 in repair manual microfiche for models beginning with 1985 models. Mount final drive on Special Tool 33 1 010. Drain oil. Unscrew case cover. Installation: Replace gasket. Tightening torque*. Add oil - oil volume*. See Group 33 in Operating Material Binder for grade of oil.  33 10 010 * See Specifications
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Remove differential - see 33 13 611. Pry off drive flanges with a tire iron for this purpose. 33 13 611
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Mark bearing cap with punch marks and unscrew. Important! Don´t mix up bearing caps and shims to make friction torque adjustments easier. |  |
Remove complete differential case. Important! Don´t bend the pulse spider. |  |
Press pulse spider off of differential case. Important! Don´t bend the pulse spider. |  |
Installation: Press on pulse spider with Special Tool 33 1 304. |  |
Pull off tapered roller bearing on differential case with Special Tool 33 1 300. |  |
Remove ring gear (cold). |  |
Installation: Press on new tapered roller bearings cold with Special Tool 33 1 020. Important! Always only install both bearings of same make. |  |
Lift shaft seals out of both bearing caps. |  |
Press out bearing outer races with Special Tools 33 1 350 and 33 1 351. Important! Puller must engage in bearing outer race. |  |
Installation: Press in new bearing outer races with Special Tool 33 1 365. |  |
If only differential bearings are being replaced, the drive pinion can remain installed and the differential case is installed without the ring gear to determine thickness of shims. Important! Note make of bearings - needed for friction torque determination. |  |
Lubricate new bearings with approved final drive gear lube** thoroughly and let them drip dry. ** See Group 33 in Operationg Material Binder
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Install side bearing caps as marked with correspoding shims (1), but without O-rings (2) at first. Tighten bolts of bearing cap opposite the ring gear end uniformly. Tightening torque*. * See Specifications
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Compensating bores (1), recognized on the outside by tab (2), always face up in installed position of the transmission. |  |
Axial preload force of differential case bearings (400 N = 882 lbs.) can be determined with help of the friction torque*. Tighten bolts of second bearing cap uniformly only enough, that the differential can still be turned easily. * See Specifications
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Apply an output flange on the side tightenend to the tightening torque and measure the friction torque with a locally made clamp with a welded nut and friction torque meter 00 2 000. Turn friction torque meter at speed of approx. 50 rpm. |  |
The friction torque* specified in the differential case bearing table* should be reached, but not exceeded. If new shaft seals have already been installed, 20 Ncm (2 in.lbs.) must be added for each seal in which an output shaft runs while measuring. * See Specifications
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If the specified friction torque is not reached, even though both bearing caps are bolted with the specified tightening torque*, a thinner shim must be installed on the end opposite the ring gear and measuring repeated. * See Specifications
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If the friction torque is reached, even though the second bearing cap has not yet been tightened to the correct tightening torque*, a thicker shim must be used on the ring gear end and the measuring procedures repeated. * See Specifications
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To make finding the shim thickness easier, the distance between the shim and case can be measured with a feeler gage blade and added to the thickness of the used shim. |  |
Example: Second bearing cap not tightened fully (bolts screwed in uniformly). Specified friction torque* (e.g. 190 Ncm = 16.5 in.lbs.) is reached, but without shaft seals. Gap measured with blade of feeler gage ..................0.20 mm (0.008´´) Used shim thickness........1.40 mm (0.055´´) __________________________________ Install shim of thickness...1.60 mm (0.063´´) and measure again. * See Specifications
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Remove differential case. Arrange side covers and shims of determined thickness and don´t mix them up. |  |
Installation: Clean tapped bores thoroughly (with tapper). Heat ring gear to max. 100°C (212°F), checking temperature with a thermo-color pencil. Mount ring gear with two locally manufactured staybolts for guiding. |  |
Install new bolts with Loctite No. 270. Tighten bolts in order of 1 ... 10. Tightening torque*. Then tighten bolts with torque angle*. * See Specifications
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Install differential with ring gear and pulse gear. Install side covers as marked with corresponding washers (1) and new O-rings (2). Tightening torque*. * See Specifications
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Backlash/Tooth Contact Adjustments: Mount Special Tool 00 2 500 and measure the backlash*. Important! The tooth contact pattern is always most important for a perfectly adjusted pinion/ring gear set. See "Replacing Drive Pinion and Ring Gear" in 33 12 551 for general instructions on tooth contact pattern adjustments. * See Specifications 33 12 551
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To check the tooth contact pattern, coat the ring gear teeth with printer´s ink, turn in both directions several times and stop ring gear suddenly with a piece of hard wood. |  |
Correct backlash* and tooth contact pattern by changing the thickness of both sims (1). If backlash is excessive, use a thinner shim on the ring gear end. If backlash is too small, use a thicker shim on the ring gear end. An axial displacement of the ring gear by 0.01 mm (0.0004´´) will cause a change in backlash of 0.0076 mm (0.0003´´). Important! The total thickness of both shims must not be changed. * See Specifications
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If a thinner or thicker shim is required to correct the tooth contact pattern, the total thickness must be corrected with the second shim, since otherwise the friction torque of bearings would be changed again. |  |
Installation: Dip shaft seal in final drive gear lube. Drive in shaft seal against the stop with Special Tools 33 1 230 and 00 5 500. Replace a drive flange with seriously scored bearing surfaces. |  |
Installation: Place round wire snap ring (1) in groove of differential case prior to installation of the drive flange in such a manner, that both ends of the snap ring are recessed in groove. This prevents lateral bending of the ring. Press in drive flange by hand and turn slightly until the snap ring is heard to engage. Replace stretched snap rings. |  |
