Differential Adjustments
Ring gear/pinion MUST be adjusted if gears themselves have been replaced. If other parts which affect position of pinion are to be replaced, pinion depth R MUST be measured before disassembling, and pinion set to this dimension when assembling.
Differential Pinion/Side Gears, Adjusting End Play
NOTE: Spacer sleeve ensures adequate backlash between side gears and differential pinion gears even when there is axial pressure on side gears. If differential housing, cover, side gear or spacer sleeve is replaced, size of spacer sleeve must be determined again.
- Measure shortest spacer sleeve, Part No. 002 517 241, with micrometer and mark dimension on sleeve with electric marker or similar device. Sleeve should then always be used as measuring sleeve
- Place side gear (with short shaft) and both thrust washers in cover
- Attach clamping sleeve VW 381/5a and clamp gear tightly against cover
- Place side gear (with long shaft) in differential housing
- Insert measuring sleeve, and bolt housing and cover together with 4 M8 x 20 bolts
- Install dial indicator with 3 mm range
^ A = M10 x 25 bolt
^ Dial indicator extension VW381/13 = 52mm
- Zero dial indicator with 2 mm preload
- Find end play by moving side gear up and down
- Add measured play and length of measuring sleeve together. Find this figure in table under x range and select proper sleeve
- Disassemble differential and remove measuring sleeve
- Install sleeve selected from above table and assemble differential without differential pinion shaft
- Recheck play. Play should be 0.03-0.17 mm
Ring Gear/Pinion, Adjusting
NOTE: Ring gear/pinion must always be replaced as matched set, never individually.
Explanation of Ring Gear/Pinion Markings
- Service gears
1 = Marking K 738 means Klingelnberg gear set with ratio of 7:38 teeth
2 = Matching number of gear set 312
3 = Deviation r based on master gauge used in special test machine in production. Deviation r is always given in 1/100 mm. 25 shown in example means that r = O.25 mm
Ro = Length of master gauge in production: Ro = 63 mm
R = Actual dimension between ring gear centerline and end face of pinion at quietest running point for this gear set
Vo = Hypoid offset = 10 mm
- Production gears
X = Markings x'ed-out are not shown on production gears
Po = Setting dimension for production gears
CAUTION:
- In production, position of pinion is determined by dimension Po (ring gear centerline to back of pinion head).
- Marking of deviation r on ring gear and matching number have been discontinued. It is therefore necessary to measure position of pinion before removing it when parts which affect position of pinion are to be replaced.
Ring Gear/Pinion Adjustment Procedure
CAUTION: Maximum possible care and cleanliness during all assembly and measuring operations are essential for satisfactory results.
Ring gear/pinion adjustment points:
- S1 = Screw-in depth of adjusting ring (ring gear side)
- S2 = Screw-in depth of adjusting ring (housing side)
- S3 = Shim for pinion
Work Sequence:
- Find screw-in depth S1 and S2
- Tapered roller bearing preload is determined by ring gear turning torque
- Adjust pinion and check S3
- Adjust pinion with shims so that correct dimension R is attained
- Adjust backlash
Finding Position Of Pinion (actual dimension)
NOTE: Finding the position of the pinion is only necessary when deviation r is not marked on the ring gear, and parts are to be replaced which directly influence the position of the pinion. These are: both pinion bearings and transmission housing.
- Remove differential housing
- Assemble measuring bar and place it in transmission housing
- Set gauge VW 385/30 to Ro = 63.00 mm, place on bar and zero dial indicator (3 mm range) with 1 mm preload
- Measure difference from Ro. This measurement corresponds to deviation r. Note reading Example: r = 0.25 mm
- After installing new parts, adjust pinion. Deviation r is used to determine thickness of shim S3
Pinion, Adjusting
- Install tapered roller bearing and needle bearing inner race for 1st gear on pinion shaft
- Torque needle bearing inner race to 210 Nm (152 ft lb)
- Install pre-assembled pinion in transmission housing without shim S3
- Install retaining ring and tighten with VW 381/14 to 225 Nm (162 ft lb)
- Back off and retighten to 225 Nm (162 ft lb)
Finding Dimension e
- Screw in one adjusting ring until flush with transmission housing
- Adjust setting ring on measuring bar VW 385/1 to dimension -- a = approx. 57 mm
- Assemble measuring bar as shown
^ Dial gauge extension VW 385/16 = 12.3 mm
- Place measuring disc VW 385/17 on end of pinion
- Place measuring bar in housing and screw 2nd adjusting ring in until flush with housing
- Move 2nd centering ring VW 385/4 outward with movable setting ring on measuring bar until bar can just be turned by hand
- Set universal gauge VW 385/30 to Ro = 63.00 mm and place it on measuring bar
- Zero dial gauge (3 mm range) with 1 mm preload
NOTE: Gauge VW 385/11 can be used instead of universal gauge VW 385/30.
- Turn bar until measuring pin touches measuring disc on end of pinion, and needle shows maximum deflection. This is dimension e Example: e = 0.40 mm
Shim S3, Determining Thickness
- S3 = e + r
^ e = measured figure (max. deflection)
^ r = deviation (marked on ring gear in 1/100 mm or found by actual measurement)
Example:
Dial gauge reading for e 0.40 mm
Deviation r +0.25 mm
___________
S3 shim thickness =0.65 mm
- Select shim from table (reference image)
NOTE:
- Shim tolerances make it possible to select any required thickness for S3
- Measure shims at several points with micrometer and check for burrs and damage
- Use only shims which are in good condition
Adjustment (dimension r), Checking
- Install pinion with measured shims S3 and turn several times in both directions
- Place measuring bar in position and check measurements
- If shims have been selected correctly, dial gauge (reading counterclockwise), should show deviation r within tolerance of 0.04 mm
Ring Gear, Adjusting (pinion removed)
CAUTION: Differential bearing outer races must be fully seated in adjusting rings.
- Install differential with ring gear on driver's side
- Install dial indicator (3 mm range) with extension VW 382/9 into bar VW 382/7
- Zero dial indicator with 1 mm preload
- Turn in adjusting ring on ring gear side with VW 381/15 until upper edge is approximately 0.20 mm below surface of housing
- Turn in adjusting ring on other side with VW 381/15 until differential is free of play and without preload
- Attach VW 381/5a to ring gear side and lock with hex nut
- Turn transmission housing so differential is at top and attach bridge VW 381/8 on dowel pins
- Attach torque gauge US 1064
- Turn differential in both directions while oiling bearings with transmission oil
- Increase bearing preload slowly by turning in adjusting ring on side opposite ring gear with VW 381/15 while turning differential with US 1064 until specified turning torque is reached
^ Turning torque:
New bearings -- 300-350 Ncm (27-31 in lb)
Used bearings (run at least 30 miles) -- 30-70 Ncm (2.7-6.2 in lb)
- Measure screw-in depth of adjusting rings and note readings S1 and S2
- Mark adjusting rings and do not interchange
NOTE: If ring gear is being readjusted, check pinion adjustment.
Backlash, Adjusting
- Install pinion with shim S3
- Install differential with adjusting rings on correct sides
- Attach bridge VW 381/8
- Turn in adjusting rings while turning differential until measured screw-in depths S1 and S2 have been reached
- Attach measuring tools as shown
- Lock pinion with clamp
^ A = bolt M8 x 125
- Turn ring gear to stop and set dial indicator to zero
- Turn ring gear in opposite direction and read backlash
- Check backlash each 1/4 turn
- Backlash should be 0.15-0.25 mm (0.006-0.010 in.)
NOTE: Individual readings must not differ from one another by more than 0.05 mm.
CAUTION: If backlash readings vary by more than 0.06 mm from one another, there is something wrong with the installation of ring gear or gear set itself. Check all assembling operations and replace gear set if necessary.
- To adjust backlash, proceed as follows:
^ Turn adjusting ring on side opposite ring gear OUT
- Turn adjusting ring on ring gear side IN by same amount
- Continue adjusting until backlash is -- 0.15-0.25 mm (0.006-0.010 in.)
NOTE: Keep within tolerance of ±0.01 mm
- Check backlash each 1/4 turn
- Backlash should be 0.15-0.25 mm (0.006-0.010 in.)
NOTE: Individual readings must not differ by more than 0.05 mm