Pinion Shaft, Adjusting
Pinion shaft, adjusting
Special tools and workshop equipment required
- VW 204 B Crankshaft seal insertion tool
- VW 296 Transmission removal lever
- VW 385 Universal measuring set
- VW 387 Universal dial gauge bracket
- VW401 Press plate
- VW 407 Press tool
- VW519 Tube
- 3253 Fitting tool
- 3005 Press disk
- 3128 Puller
- 3301 Assembly tool
- VAG1331 Torque wrench
It is only necessary to readjust the pinion shaft as described below when the gear set, pinion shaft taper roller bearing or transmission housing has been replaced.
Determining total shim thickness "S_total" (S3 plus S4)
(Adjusting pinion shaft taper roller bearings preload).
- Differential removed.
- Install large taper roller bearing outer race without shim in transmission housing.
- Insert (rubber) disc, and pressure plate.
Pressure plates with different thicknesses can be installed:
For aluminum transmissions: 14.8 mm or 15.3 mm.
For magnesium transmissions.
- Press outer race of small taper roller bearing with a temporary shim S4* with a thickness of 1.00 mm into transmission cover to stop.
As a prerequisite for the measurement, a temporary S4 shim of 1.00 mm is inserted. It is designated S4* below. After the determination of the measurement "e", S4* is replaced with the final S4 shim.
- Press on inner race of large taper roller bearing.
- Secure lower taper roller bearing (arrow).
- Press on inner race of small taper roller bearing.
- Insert pinion shaft in transmission housing.
- Fit transmission cover and tighten bolts to 22 Nm.
- Turn transmission so that the transmission cover is downwards.
- Press on face of pinion shaft with lever VW 296 until outer race of small taper roller bearing contacts transmission cover.
- Continue to press face of pinion shaft while turning pinion shaft 8 revolutions by hand so that the taper bearing settles.
- Mount dial gauge (3mm measuring range) and set to "0" with 2mm preload.
- Use 30 mm dial gauge extension.
The D.T.I. extension must be positioned on the ground face of the pinion shaft.
- Turn transmission 180° so that the transmission cover is upwards.
- Turn pinion shaft by hand 8 turns so that the taper roller bearing settles.
Otherwise the measurement will not be accurate
- Move pinion shaft up and down without turning it, read off play from dial gauge and record it. (Example: 0.45 mm)
Determine S_total (S3 and S4)
- Turn pinion shaft and set dial gauge to "O" with 2 mm preload before each measurement so that the measurement is not falsified.
The specified bearing preload is obtained by adding a constant preload figure (0.15 mm) to the measured value (0.45 mm) and inserted shim S4* (1.00 mm).
S_total = S4* + measured value + preload
Example:
Determining temporary shim "S3*" thickness
Note: After the determination of measurement "e", the temporary shim S3* is replaced with the final shim S3.
Temporary shim S3* = S_total - S4*
Example
- Remove outer race of large taper roller bearing.
- Insert temporary shim S3* in transmission housing and re-install outer race.
- Insert pinion shaft in transmission housing.
- Fit transmission cover and tighten bolts to 22 Nm.
Checking pinion shaft taper roller bearing preload:
- Fit M10 x 20 bolt to pinion shaft and turn pinion shaft at least 8 turns so that the taper roller bearings settle.
- Remove bolt.
- Fit measuring tools and secure with bolt (arrow) to transmission housing.
- Mount dial gauge (3 mm measuring range) centered on transmission cover and set to zero with 2mm preload.
- Loosen transmission cover bolts and turn pinion shaft several times.
- If the correct shim has been selected the D.T.I. will indicate a value of 0.05 mm to 0.15 mm.
- Retighten transmission cover bolts to 22 Nm.
- Remove measuring tools.
- Fit M10 x 20 bolt to pinion shaft and turn pinion shaft at least 8 turns so that the taper roller bearings settle.
- Remove bolt
Determining dimension "e"
- Set universal mandrel VW 385/1 setting ring to dimension a = 45mm.
- Set sliding positioning ring to dimension b = 75 mm.
Note: Dimension "e" is necessary for determining thicknesses of final shims "S3" and "S4".
- Arrange universal mandrel as illustrated.
Note: Centering ring VW285136 must be used instead of VW285/3 on dial test indicator side for transmissions with enlarged taper roller bearing.
- The D.T.I. extension -A- must be selected from the table:
D.T.I. extension - A - Ro Ring gear
9.3 mm e.g. VW 385/15 59.65 mm 180 mm
6.5 mm 54.95 mm 170 mm
Set master gauge VW 385/30 to Ro according to ring gear and place on measuring mandrel.
Ring gear 0 180 mm Ro = 59.65 mm
Ring gear 0 170 mm Ro = 54.95 mm
- Set D.T.I. (3 mm measuring range) to zero with 2 mm preload.
- Remove master gauge.
- Place end measuring plate on face of pinion shaft.
For transmissions without enlarged taper roller bearing on cover side
- Insert universal mandrel in housing.
- For Ro = 54.95mm a 6.5mm D.T.I. extension must be used instead of the D.T.I. extension VW 385/15.
For transmissions with enlarged taper roller bearing on cover side
- Insert universal mandrel in housing.
- For Ro = 54.95mm a 6.5mm D.T.I. extension must be used instead of the D.T.I. extension VW 385/15.
Continued for all transmissions
- Fit final drive cover and tighten the 4 bolts to 22 Nm.
- Using sliding setting ring to pull 2nd centering disc outwards until mandrel can still just be turned by hand.
- Measure dimension "e". Turn mandrel until tip of D.T.I. extension makes contact with end measuring plate and indicates max. deflection (return point). The measured value is dimension "e".
- Depending on the installed height of the pinion shaft, dimension "e" may be located in either the "red" or the "black" number range.
Determining shim "S3" thickness
Notes:
- If the measurement is in the red number range, the measurement "e" must be subtracted.
- If the measurement is in the black number range, the measurement "e" must be added.
- The deviation "r" in respect to master gauge "Ro" is measured for the gear sets supplied as replacement parts and is given on the outer circumference of the ring gear.
S3 = S3* + r + e
("e" in black number range)
S3 = S3*+ r-e
("e" in red number range)
Example:
Note: Allocate shims according to parts catalog.
Shims available for S3
- Different tolerances make it possible to select the exact thickness of shim(s) required.
Determining shim "S4" thickness
S4 = S_total - S3
Example
Note: Allocate shims according to parts catalog.
Determining shim "S4" thickness
- Different tolerances make it possible to select the exact thickness of shim(s) required.
Carry out check measurement - checking dimension "r"
- Install pinion shaft with measured shims S3 and S4 and turn in both direction several times.
Insert universal mandrel and measure dimension "r".
If the correct shims have been selected the D.T.I. must now indicate the mark dimension "r" (reading anti-clockwise on red scale) within a tolerance of ± 0.04 mm.
Shim "S4", determining thickness when replacing transmission cover
Special tools and workshop equipment required
- VW 387 Universal dial gauge bracket
- VW 792 Assembly tool
- Use depth gauge with precision of at least 5/100 mm.
- Measure difference of depths "a" in old and new transmission housing.
Example:
- Install thicker shim S4 if the new transmission cover is deeper.
- Install thinner shim S4 if the old transmission cover is deeper.
Example:
Note: Allocate shims according to parts supplier.
- Insert outer race for taper roller bearing with shim S4 in transmission cover.
- Fit transmission cover and tighten bolts to 22 Nm.
Checking pinion shaft taper roller bearing preload:
- Turn pinion shaft at least 8 turns in both direction before each measurement so that the taper roller bearing settle.
Note: The pinion shaft can be rotated by simultaneously rotating both flanged shafts.
- Fit measuring tools and use bolt -arrow- to secure to transmission housing.
- Attach dial gauge (3 mm measuring range) centered on transmission housing to zero with 2 mm preload.
- Loosen transmission cover bolts and rotate pinion shaft.
- If the correct shim has been selected, dial gauge will indicate a value of 0.05 mm to 0.15 mm.
- Remove measuring tools.
- Retighten transmission cover bolts to 22 Nm.