Pinion Adjusting
Adjusting Output Shaft
Adjustment of the pinion as explained here is only necessary when the gear set has been replaced. When other parts that also influence the position of the pinion have been replaced, the setting is performed by measuring the adjustment position before removing the pinion (actual measurement). Refer to Ring and Pinion Gear Set, List Of Adjustments.
Determining Total Shim Thickness Stotal (S3 + S4)
(Adjusting preload of pinion tapered roller bearings)
- Install outer races of tapered roller bearings, without shims, in transmission housing and cover.
- Always install shim (rubber) and pressure plate to measure shim thickness and to determine thickness of shim S4.
Note: Pressure plates of varying thicknesses (14.8-15.3 mm) can be installed.
- Install inner races for tapered roller bearings
- Secure lower tapered roller bearing (arrow).
- Place pinion in transmission housing.
- Install transmission cover and tighten bolts.
^ Tightening torque: 25 Nm (18 ft lb)
- Turn assembly so that cover is at bottom.
- Press on pinion head with removing lever VW 296 until outer race of tapered roller bearing makes contact with transmission cover.
- Turn pinion by hand until tapered roller bearing has settled into position.
- Set up measuring fixture and turn dial indicator to zero, with 1 mm preload.
- Turn transmission 180° so that cover is at top.
- Turn pinion by hand until tapered roller bearing settles.
CAUTION! Before taking the measurement, turn the pinion so that the tapered roller bearing can settle. Otherwise the measurements will be incorrect.
- Note reading on dial indicator.
Example: Reading on dial indicator 1.45 mm
Determine Stotal (S3 and S4) Stotal = gauge reading + preload
Preload (design value, constant) 0.15 mm
+ Gauge reading (example) 1.45 mm
= Stotal 1.60 mm
Checking Preload Of Tapered Roller Bearings For Pinion:
- Using calculated total thickness (Stot = I, 1.60 mm in example above) select shim from table (described below) and install behind tapered roller bearing outer race in transmission cover (S4 side).
- Install transmission cover.
- Install bolt on pinion head and turn pinion several times so that bearings can settle.
- Remove bolt.
- Set up measuring tools.
- Secure bolt (arrow) on transmission housing.
- Set dial indicator (3 mm range) to zero with 1 mm preload.
- Loosen transmission cover bolts.
If shims have been selected correctly, dial indicator should now indicate value from 0.08 mm to 0.15 mm.
Determining Dimension e
- Leave shim of calculated thickness (1.60 mm in example) in place behind tapered roller bearing outer race in transmission cover (S4 side).
- Install transmission cover again.
- Install bolt on pinion head and turn pinion several times so that bearings can settle.
- Remove bolt.
- Adjust setting ring of universal barrel gauge VW 385/1.
- Dimension -a- 35 mm
- Adjust sliding ring.
- Dimension -b- = 75 mm
- Set up universal measuring bar as shown.
* Ring gear diameter 170 mm: Ro = 54.95 mm; dial indicator extension = 6.5 mm
* Ring gear diameter 180 mm: Ro = 59.65 mm; dial indicator extension = 9.3 mm
- Adjust master gauge VW 385/30 as follows:
* Place master gauge on measuring bar and set dial indicator (3 mm range) to zero with 1 mm preload.
- Lay end plate VW 385/33 onto pinion head.
- Remove master gauge and insert measuring bar into housing.
Centering washer VW 385/33 faces final drive cover.
- Install final drive cover and tighten four bolts.
- Using sliding ring, pull 2nd centering washer out just far enough so that bar can just be turned by hand.
- Measure dimension e.
- Turn measuring bar until dial indicator extension touches end plate at pinion head and indicates max deflection (reversal point).
Measurement dimension e (black gauge range)
Example: 0.46 mm
Position Of Measuring Tools To Determine Dimension e
Determining Thickness Of Shim S3
S3 = e + r
e - Gauge reading (max. deflection)
r - Deviation (marked on ring gear in units of 1/100 mm, or determined by actual measurement)
Example:
Value of e shown on dial indicator 0.46 mm
+ Deviation r marked on ring gear 0.18 mm
= Thickness of shim S3 0.64 mm
The tolerances in nominal shim sizes make it possible to choose a shim with the precise thickness required for S3.
Available Shims S3
Determining Thickness Of Shim S4
S4 Stotal - S3
Example:
Total shim thickness 1.60 mm
- Thickness of shim S3 0.64 mm
= Thickness of shim S4 0.96 mm
The tolerances in nominal shim sizes make it possible to choose a shim with the precise thickness required for S4.
Available Shims S4, Chart 1 of 2
Available Shims S4, Chart 2 of 2
Checking Measurements
Check dimension r:
- Install pinion with measured shims S3 and S4 and turn several times in both directions.
- Insert universal measuring bar and check measurements.
If shims have been selected correctly, the dial indicator, reading counter-clockwise (red gauge range), must indicate inscribed value of deviation 'r' within tolerance of ± 0.04 mm.