Ring and Pinion
Replacing input bevel gear and crown wheel (Type M) - final drive housing removed -
Remove and install final drive, refer to Complete Assembly, Replacement.
Securing final drive to special tool 33 1 010 (retaining bracket).
Drain ATF. Take off case cover.
Installation:
Replace gasket.
Tightening torque, refer to Specifications
Add oil.
Oil volume, refer to Specifications.
Press off both drive flanges with a tire iron.
Installation:
Place round wire snap ring (1) in groove of differential case prior to installation of the drive flange, that both ends are recessed in the groove.
This prevents lateral bending of the ring.
Press in drive flange by hand and turn slightly until wire snap ring is heard to engage.
Replace stretched snap rings.
Punch mark both bearing caps.
Unscrew and remove both bearing caps.
Caution:
Don't mix up bearing caps and spacers.
Secure spacers on bearing cap with a piece of wire, if necessary.
Installation:
Tightening torque, refer to Specifications.
Final drive housing bearings and backlash are adjusted with shims (1).
Check O-ring (2), replacing if necessary.
Remove complete final drive housing.
Caution: Don't bend the pulse spider.
Remove lockplate.
Unfasten nut (1) and brace with special tool 23 0 020.
Remove input flange with special tool 33 1 150.
The specified friction torque for the new input bevel gear bearing is indicated, refer to Specifications
The friction torque of old bearings does not have to be measured.
Press out drive pinion.
Extract front bearing outer race with special tool 33 1 350 (fixture).
(1) Spreader
(2) Front bearing outer race
(3) Puller bell housing
(4) Pressure bolt
Extract rear outer bearing race with special tool 33 1 360 (fixture).
Puller consists of:
Special tool 33 1 351 (extractor head)
Special tool 33 1 362 (threaded spindle)
Special tool 33 1 356 (support bridge)
Special tool 33 1 363 (pressure nut)
Caution:
Shim (X) is located underneath the rear bearing outer race.
It will be needed again for pinion/crown wheel adjustments.
Caution: Replace both drive pinion bearings, using only one make.
Install old shim (X) in front of the rear bearing outer race.
Install new bearing outer races with special tool 33 1 360 (installation fixture).
Puller consists of:
Special tool 33 1 373 (puller disc for front outer race)
Special tool 33 1 365 (puller disc for rear outer race)
Special tool 33 1 362 (threaded spindle)
Special tool 33 1 363 (pressure nut)
Special tool 33 1 354 (nut)
Press-fit new taper roller bearing inner race to new drive pinion using special tool 33 1 020 (sleeve).
Caution:
Drive pinions and crown wheels are paired for optimal smooth running in special machines.
The pairing code (P) is inscribed electrically on the drive pinion and crown wheel.
Never install crown wheel and drive pinion with different pairing codes (P) together.
H = Gleason hypoid teeth (helical shape).
The inscribed number with "+" or "-" is the deviation from basic distance C in hundredths of millimeters and is required for adjustment of the tooth contact pattern with shims.
+ e is added to C.
- e is subtracted from C.
To determine the thickness of shim (X), install drive pinion with new tapered roller bearings, but without bush.
Install drive pinion in the rear bearing outer race.
Press-fit front taper roller bearing to the drive pinion with special tool 23 1 300 in conjunction with a spacer bush but do not tighten down.
Mount input flange.
Gradually tighten collar nut, occasionally measuring friction torque with special tool 00 2 000 (friction torque gauge) and adjust with collar nut to 250 Ncm.
Block Distance of Drive Pinion
Secure dial gauge in special tool 33 1 481 (measuring fixture).
Place special tool 33 1 461 (measuring fixture) with dial gauge on special tool 33 1 462 (measuring discs) and set dial gauge with preload at zero.
Fit special tool 33 1 462 (measuring disc) to drive pinion.
Install special tool 33 1 461 (measuring fixture) in housing.
Determine value Y.
Basic distance C = 11.50 mm
Gage thickness B = 9.50 mm
Examples for Determination of Correct Shim Thickness (X)
Example I:
C 11.50 mm
e + 0.10 mm
C nominal 11.60 mm
Y measured on dial gage 1.90 mm
+ gage thickness B 9,50 mm
C actual 11.40 mm
C nominal 11.60 mm
C actual - 11.40 mm
a 0.20 mm
Master disc A 4.10 mm
-a 0.20 mm
Thickness of shim (X) 3.90 mm
If C nominal is greater than C actual, "a" is subtracted from thickness of shim (X).
Example II:
C 11.50 mm
e - 0.10 mm
C nominal 11.40 mm
Y measured on dial gage 2.20 mm
+ master disc thickness 9.50 mm
C actual 11.70 mm
C nominal 11.70 mm
C actual 11.50 mm
a 10.20 mm
Master disc A 3.90 mm
- a 0.20 mm
Thickness of shim (X) 4.10 mm
If C Nominal is less than C Actual, "a" on the shim ring (x) is added to the value.
The permitted tolerance for dimension (x) is derived from the gage steps available for shim rings (0.01 through 0.03 mm)
Remove drive pinion and rear bearing outer race.
Press in shim (X) of determined thickness and bearing outer race.
Caution: Do not install the drive pinion at this point, since it is first necessary to measure and adjust the friction torque of the new final drive housing bearing.
Press pulse spider (3) off of final drive housing.
Caution: Don't bend the pulse spider.
Installation:
Press fit pulse generator wheel with special tool 33 1 358 (pressure sleeve).
Remove crown wheel (cold).
Installation:
Clean tapped bores thoroughly (tapper).
Heat plate spring to max. 100° C (thermo-chrome pin).
Mount crown wheel with two locally manufactured staybolts for guiding.
Install new bolts with Loctite No. 270 and tighten in order of 1 through 10.
Tightening torque and torque angle, refer to Specifications
Extract taper roller bearing on final drive housing with special tool 33 1 300 (extractor).
Installation:
Press-fit new taper roller bearing inner races cold with spe6 tool 33 1 003 (sleeve).
Lift shaft seals out of both bearing caps.
Press out outer bearing race with special tool 33 1 350 (extractor fixture) and special tool 33 1 351 (extractor star tool).
Caution:
Special Tool must engage in the bearing outer race.
Installation:
Press-fit new bearing outer races with special tool 33 1 365 (pressure plate).
The following 12 steps can only be omitted, if the final drive housing bearings were not replaced.
Install final drive housing with new crown wheel and new bearings.
Lubricate bearings thoroughly with approved final drive gear lube and let them drip dry.
Install side bearing caps marked with belonging shims (1), but at first without O-rings (2).
Evenly tighten bearing cover screws opposite the crown wheel.
Tightening torque, refer to Specifications
The compensating bore (1), recognized on the outside by tab (2), always faces up in installed position of the transmission.
Determining Friction Torque of New final drive housing Bearings
Axial preload force of final drive housing bearings (4000 N) can be determined with help of the friction torque, refer to Specifications
Tighten bolts of second bearing cap uniformly only enough, that the differential can still be turned easily.
Install an output flange on the side opposite the crown wheel Determine friction torque using a bracket with welded on nut (in-house manufacture) and special tool 00 2 000 (friction torque gauge).
Turn friction torque meter at speed of approx. 50 rpm.
The friction torque specified in the final drive housing bearing( table should be reached, but not exceeded.
If new shaft seals have already been fitted, 20 Ncm must be added to each sea[ in which an output shaft rotates during & measurement process, refer to Specifications
If the given friction torque is not reached, even though both bearing caps are tightened to the correct tightening torque, install a thinner shim opposite the crown wheel and repeat the measuring procedures.
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 crown wheel end and the( measuring procedures repeated.
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 (bolts screwed in uniformly)
Specified friction torque reached and shaft seals not yet installed.
Gap measured with blade 0,20 mm
Used shim 1,40 mm
Install shim of thickness 1,60 mm
Install new shims, 1.60 mm gage, and repeat measurement.
Remove differential for installation of the drive pinion.
(If final drive housing bearings were not replaced, procedure can be continued from this point.)
Caution: Match side covers ad corresponding shims of determined thickness; don't mix them up.
Install drive pinion with a new clamping sleeve (2).
Immerse shaft seal in final drive oil and drive home flush with special tool 33 1 270 in conjunction with special tool 00 5 500 (handle).
Press-fit input flange to the input shaft using special tool 23 1 300 but do not tighten down.
The axial preload force of drive pinion bearings (5000 N) can be determined with help of the friction torque.
Tighten input flange with the collar nut in steps, measuring the friction torque after each step.
Measure friction torque with special tool 00 2 000 and suitable socket head, refer to Specifications.
Caution:
The relation between friction torque and preload force differs depending on the make of bearings.
Take specified friction torque from the pinion bearing table and add 20 Ncm, refer to Specifications.
Install differential. Install side covers as marked with corresponding washers (1) and new O-rings (2). Tighten bolt uniformly.
Tightening torque, refer to Specifications
Backlash/Tooth Contact Pattern Adjustment
Attach special tool 00 2 500 (dial gauge holder) and measure torsional face runout, refer to Specifications
Caution: The tooth contact pattern is always most important for a perfectly adjusted pinion/crown wheel.
To check the tooth contact pattern, coat the crown wheel teeth with printer's ink, turn in both directions several times and stop crown wheel suddenly with a piece of hard wood.
Correction of torsion clearance and contact pattern is performed by altering the thickness of both shims (1).
If the backlash is too large, install a thinner shim on the crown wheel end.
If backlash is too small, use a thicker shim on the crown wheel end.
Axial displacement of the crown wheel of 0.01 mm signifies a change in tooth flank clearance of 0.0076 mm.
Caution:
The total thickness of both shims must not be changed.
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 new shaft seals in final drive gear lube.
Drive shaft seal firmly home with special tool 33 1 230 (impact bush) in conjunction with special tool 00 5 500 (handle).
Replace drive flange if the bearing surface is seriously scored.
Note: It is possible that the special tool 33 1 230 might have to be reworked to compensate for casting tolerances on the side cover.
Drive in new retaining plate with special tool 33 4 050 and special tool 00 5 500 (handle).