Drive Pinion, Adjusting
Drive Pinion and Ring Gear Adjusting
• General notes:
• 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 the adjustment is to reproduce the setting for quietest possible running, as obtained on the test machine in production.
• The deviation "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) must only be replaced together as a matched pair.
• Observe the general repair instructions for taper 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 measuring tool (VW385)
• holding fixture (VW540)
• Before adjusting the drive pinion adjust the ring gear (ascertain total shim thickness "S" for shims "S1" + "S2"). Refer to => [ Ring Gear, Adjusting ].
• Readjustment of the drive pinion is only necessary if the final drive set, taper roller bearing for drive pinion or housing for final drive is replaced. Refer to => [ Adjustment Overview ].
• Do not oil new taper roller bearings for frictional torque measurement. The bearings have already been treated with special oil by the manufacturer.
Shim S3, Determining Thickness
(Setting preload of taper roller bearing for drive pinion)
- Clamp final drive into assembly bracket. Refer to => [ Securing Rear Final Drive to Assembly Fixture ] Rear Final Drive 01R (01AA,01EA,02XA,0A3A,01V,01VA,09LA Transmission).
- Insert both outer races for the taper roller bearing without shims into the housing, refer to => [ Pulling in outer race for large taper roller bearing ] Drive Pinion, => [ Pulling in outer race for large taper roller bearing ] Drive Pinion and => [ Pressing in small taper roller bearing outer race ] Drive Pinion
- Insert drive pinion without spacer sleeve.
- Heat inner race for taper roller bearing to approximately 100 °C and install onto drive pinion.
CAUTION!
Wear protective gloves!
• Only install spacer sleeve for final frictional torque measurement (after determining shim "S3").
• Install new taper roller bearings in delivery condition and do not oil.
- Mount flanges for drive shaft and tighten hex nut for the flange, refer to => [ Installing flange ] Drive Pinion
A - Torque gauge, commercially available, 0 to 600 Nm
B - Socket, A/F 36
- Tighten drive pinion nut until the following frictional torque is obtained.
* With at least 50 km service
- Set adjustment ring of universal mandrel (VW385/1 ).
• Distance a = 60 mm
- Set sliding adjustment ring.
• Distance b = 55 mm
- Assemble universal mandrel as illustrated.
• Dial indicator extension (VW385/15) = 9 mm long
- Set universal master gauge (VW385/30).
• Ro = 57.50 mm
- Set dial indicator (3 mm measuring range) to "0" with 2 mm preload.
- Turn drive pinion 8 turns in both directions so that the taper roller bearings settle.
- Place end measuring plate (VW385/33) onto drive pinion head.
- Remove master gauge and insert measuring mandrel in the housing.
• The centering disc for (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 the mandrel can still just be turned by hand.
Measurement e, Determining
- Turn mandrel until the dial indicator point touches the end measuring plate on pinion shaft head, then measure maximum deflection (return point). The measured value is dimension "e" (in red range).
• Measurement in following example: "e" = 1.60 mm
• Dimension "e" is required to determine thickness of shim " S3".
- Then, (after removing universal mandrel) check again that the dial indicator, with master gauge (VW385/30) installed, indicates " 0" with 2 mm preload, otherwise repeat the measurement.
Shim S3, Determining Thickness
- Determine shim(s) as accurately as possible from table.
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 for large taper roller bearing and reinstall with calibrated shims "S3" and spacer sleeves. Refer to => [ Removing nut for drive pinion ] Drive Pinion
- Insert inner race for small taper roller bearing and tighten drive pinion nut until specified frictional torque is achieved. Refer to => [ Tighten nut for drive pinion and adjusting friction torque ] Drive Pinion
• Do not oil new taper roller bearings for frictional torque measurement. The bearings have already been treated with special oil by the manufacturer.
• Only increase tightening torque slowly and read off frictional torque frequently. If the specified frictional torque is exceeded, the spacer sleeve must be replaced and the adjustment repeated. It is not possible to reuse a spacer sleeve that has been excessively compressed.
- Set to following frictional torques:
* With at least 50 km service
Performing Measurement Check
Checking dimension "r"
- Turn drive pinion 8 turns in both directions so that the taper roller bearings settle.
- Insert universal mandrel and check measurement.
• If the shims have been correctly selected, the dial indicator, reading counter clockwise (in red range), will show deviation "r" within a tolerance of ± 0.05 mm
- Peen drive pinion nut with a punch.
- The radial run out at flange for drive shaft must always be measured and marked. Refer to => [ Driveshaft Flange Measuring Radial Run Out and Marking ] Service and Repair.