Drive Pinion, Adjusting
Drive Pinion and Ring Gear, Adjusting
General Information
• Careful adjustment of the drive pinion and ring gear is important for the service life and smooth running of the final drive. For this reason, the drive pinion and ring gear are matched together during manufacture, and checked to ensure a good mesh pattern and quiet running in both directions of rotation. The position of quietest running is found by moving the drive pinion in an axial direction and at the same time lifting the ring gear out of the zero-play mesh position by the amount necessary to maintain the backlash within the specified tolerance.
• The object of this adjustment is to reproduce the setting for the quietest possible running as obtained on the test machine in production.
• The deviation (or tolerance) "r", which is related to the master gauge "Ro" is measured for the final drive sets supplied as replacement parts and marked on the outer circumference of the ring gear. The final drive set (drive pinion and ring gear) may only be replaced together as a matched pair.
• Observe the general repair instructions for tapered roller bearings and shims.
• Maximum care and cleanliness are essential for achieving good results when performing repairs and taking measurements.
Drive Pinion, Adjusting
Special tools, testers and auxiliary items required
• Universal mandrel (VW385)
• Engine and gearbox support (VW 540)
• Before adjusting drive pinion, adjust ring gear (determine total shim thickness "Stotal" for shims "S1" + "S2") => [ Ring Gear, Adjusting ]. Ring Gear, Adjusting
• The drive pinion only has to be readjusted if the final drive set (ring gear and drive pinion), the tapered roller bearings for the drive pinion or the final drive housing are replaced. Adjustment overview => [ Adjustment Overview ]. Adjustment Overview
• Do not additionally oil new tapered roller bearings for frictional torque measurement. The bearings have already been treated with a special oil by the manufacturer.
Shim S3, Determining Thickness
(Setting preload of tapered roller bearing for drive pinion)
- Mount final drive on engine/transmission support => [ Rear Final Drive, Securing to Engine/Transmission Support ] Rear Final Drive, Securing to Engine/Transmission Support.
- Insert both tapered roller bearing outer races without shims into housing => [ Pulling in outer race for large tapered roller
bearing ] Drive Pinion, => [ Pulling in outer race for large tapered roller
bearing ] Drive Pinionand=> [ Pressing in outer race for small tapered roller
bearing ] Drive Pinion.
- Insert drive pinion without spacer sleeve.
- Heat inner race for tapered roller bearing to approx. 100° C and fit onto drive pinion.
CAUTION!
Wear protective gloves.
• Only install spacer sleeve for final frictional torque measurement (after determining shim "S3").
• Install new tapered roller bearings as supplied and do not oil additionally.
- Install driveshaft flange and tighten hex nut for flange => [ Installing flange ] Drive Pinion.
- A -= Torque gauge, commercially available, 0 to 600 Ncm
- B - = Socket attachment, 36 mm A/F
- Tighten drive pinion nut until following friction torque is obtained.
* run at least 50 km (30 miles)
- Set adjustment ring of universal mandrel (VW385/1).
• Distance a = 60 mm
- Set sliding adjustment ring.
• Dimension b = 55 mm
- Assemble universal mandrel as illustrated:
• Dial gauge extension (VW385/15) = 9 mm long
- Set universal master gauge (VW385/30).
• Ro = 57.50 mm
- Set dial gauge (3 mm measuring range) to "0" with 2 mm preload.
- Turn drive pinion at least 8 turns in both directions so that tapered roller bearings settle.
- Place end measuring plate (VW385/33) onto drive pinion head.
- Remove master gauge and insert measuring mandrel in housing.
• The centering disc (VW385/3) faces toward cover for final drive
- Install cover for final drive and tighten 4 bolts.
- Using adjustable ring, move 2nd centering disc out as far as possible so that mandrel can still just be turned by hand.
Determining Measurement "e"
- Turn mandrel until dial gauge point touches end measuring plate on drive pinion head, then measure maximum deflection (return point). Measured value is dimension "e" (in red scale).
• Measurement in following example: "e" = 1.60 mm
• Dimension "e" is required to determine thickness of shim "S3".
- After removing universal mandrel, check once again whether dial gauge reads "0" with 2 mm preload when master gauge (VW385/30) is in place - otherwise repeat measurement.
Shim S3, Determining Thickness
- Determine shim(s) as accurately as possible from table. Part numbers:
Shim Table
* Using the shim tolerance variations it is possible to find the exact shim thickness required. Insert two shims if necessary.
- Remove universal mandrel.
- Remove drive pinion and outer race of large tapered roller bearing and install together with measured shims "S3" and spacer sleeve => [ Removing nut for drive pinion ] Drive Pinion.
- Insert small tapered roller bearing inner race and tighten nut for drive pinion until specified friction torque is obtained => [ Tightening nut for drive pinion and setting
friction torque ] Drive Pinion, => [ Tightening nut for drive pinion and setting
friction torque ] Drive Pinion.
• Do not additionally oil new tapered roller bearings for frictional torque measurement. The bearings have already been treated with a special oil by the manufacturer.
• Increase tightening torque slowly and check friction torque at regular intervals. If the specified friction torque is exceeded the spacer sleeve must be replaced and the adjustment repeated. A spacer sleeve which has been compressed too much cannot be reused.
- Set to following frictional torques:
* run at least 50 km (30 miles)
Performing Measurement Check
Checking dimension "r"
- Turn drive pinion 8 turns in both directions so that tapered roller bearings settle.
- Insert universal mandrel and perform check measurement.
• If the correct shims have been selected, the dial gauge should now show the value of "r" as marked on the ring gear, reading counter-clockwise in the red scale, within a tolerance of ± 0.05 mm.
- Peen drive pinion nut with a punch.
- Measure and mark radial run-out at flange for driveshaft => [ Radial Run-Out at Driveshaft Flange, Measuring ] Radial Run-Out at Driveshaft Flange, Measuring.