Ring Gear, Adjusting
Pinion and Ring Gear, Adjusting
• The pinon and the ring gear must be adjusted exactly for the service life and quiet running of the final drive. For this reason, the pinions and ring gears are paired during the manufacturing process and are checked for wear and noise. Moving the pinion by the axle adjusts the quiet running because the torsional backlash is moved within the specified tolerance.
• The difference r, in reference to the master gauge Ro, is written on the outer circumference of the ring gear.
• Replace the drive train (pinion and ring gear) together only.
Ring Gear, Adjusting
(Adjusting the differential)
• The ring gear must be adjusted if the rear axle housing, the final drive cover, the differential tapered roller bearing, the differential housing or the drive train are replaced.
Adjustment overview, refer to => [ Adjusting Overview ]. Adjusting Overview
Special tools, testers and auxiliary items required
• Magnetic Plate 50 mm Dia. (VW 385/17)
• Dial Gauge Holder (VW 387)
• Measuring Lever (VW 388)
• Sleeve (VW 521)
• Torque wrench (V.A.G 1331)
• Dial gauge
• M8 x 45 hex bolt
Determine the total Shim Thickness Stotal for the Shims S1+S2
(Adjusting the pre-load on the tapered roller bearing/differential).
• The pinion is removed.
• Only when the tapered roller bearing for the differential is being replace may the ring gear be removed from the differential housing. Then is it not necessary to remove the pinion.
- Remove the flange shaft seal using the assembly lever.
- Remove the differential tapered roller bearing and the shims. Refer to => [ Differential ] Differential.
- Install the taper roller bearing outer race all the way into the housing with a 1.00 mm shim (S2 side). Refer to => [ Differential ] Differential.
• A 1.0 mm shim S2 is installed as a preliminary measuring specification. It is identified in the following by S2*. is then replaced by S2 after the torsional backlash is determined.
- Install the taper roller bearing outer race with a shim S1 into the final drive cover.
- Install the differential into the housing.
The ring gear touches the cover side.
- Position the final drive cover and tighten the 4 bolts diagonally to 25 Nm.
- Mount the tools on the differential housing on the transmission housing side.
- Turn the final drive with the cover side upward.
- Turn the differential 8 turns in both directions so that the tapered roller bearings settle in.
- Mount the measuring tools.
- Lay the (VW 385/17) on the differential.
A - dial gauge extension 30 mm
- Install the M8 x 45 bolt - B -.
- Mount the dial gauge extension on the center of the (VW 385/17).
- Set the dial gauge (3 mm measuring range) to 0 with 2 mm preload.
- Lift the differential without rotating it in direction of - arrow -, then read the play on the dial gauge and write it down (example: 0.50 mm).
If it is necessary to repeat the measurement, then the differential must be turned 8 turns in both directions beforehand so that the tapered roller bearings settle in.
Formula: Stotal = S2* + measured value + bearing preload
Example
Shim thickness S1*
• S1* is then replaced by S1 after the torsional backlash is determined.
• The total shim thickness Stotal remains unchanged.
Formula: S1* = Stotal - S2*
Measuring the Torsional Backlash
(Position of the ring gear inside the transmission housing)
• The pinion is installed with shim S3.
• The taper roller bearing outer race is installed into the transmission housing with shims S1* + S2*.
• The differential is installed.
- Mount the final drive cover and tighten the bolts to 25 Nm.
- Turn the differential 5 turns in both directions so that the tapered roller bearings settle in.
- Mount the measuring tools.
- Install the dial gauge with the dial gauge extension (VW 382/10) (6 mm).
Set the (VW 388) to dimension a = 60 mm.
Determine the play between the tooth flanks as follows:
- Turn the ring gear until it touches one of the tooth flanks.
- Set the dial gauge to 0 with 2 mm preload.
- Turn back the ring gear until it touches the opposite tooth flank (torsional backlash).
- Read the torsional backlash and write down the measured value.
- Turn the ring gear 90° and repeat the measurement 3 times.
Determining the Average Torsional Backlash
- Add the 4 measured values and divide the total by 4.
• Result: the average torsional backlash 1.16 : 4 + 0.29 mm.
• If, during the measuring, the individual values deviate by more the 0.06 mm from each other, the ring gear or the drive train were installed incorrectly. Check the assembly and replace the drive train if necessary.
Determining the shim thickness S2
Formula: S2 = S2* - torsional backlash + lift
• The thickness can be determined by inserting one or two shims.
Determining the Shim Thickness "S1"
Formula: "S1" = "Stotal" - "S2"
• The thickness can be determined by inserting one or two shims.
- Install the shims S1 on the ring gear side and S2 opposite the ring gear. Install 2 shims if necessary.
Check Measurement
- After installing the shims S1 and S2, turn the differential 5 turns in both directions so that the tapered roller bearings can settle in.
- Measure the torsional backlash 4 times.
• Specified value: 0.12 - 0.22 mm.
• If the torsional backlash is out of the tolerance, then the adjustment must be repeated. The total shim thickness Stotal must not change.
• The individual measured values may deviate maximum 0.06 mm from each other.