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Home >> Audi >> 2021 >> Q5 Premium Plus >> Repair and Diagnosis >> Transmission >> Manual Trans >> Final Drive, Differential (7-Speed Dual Clutch Transmission 0CJ, 0CL, 0CK, 0DK, 0DN, 0DP, 0HL) >> 39 Final Drive, Differential >> Final Drive >> Final Drive, Adjusting >> Final Drive, Adjusting When Replacing Differential Or Differential Bearing >> Torsional Backlash, Measuring

Torsional Backlash, Measuring

-- Install the differential with ring gear: S 1 is on the cover side, S 2 is installed in the transmission housing.

-- Install the final drive cover and tighten the four bolts to 20 Nm.

-- Complete the Crown Wheel Adjusting Tool: VW521  (refer to Complete the as follows: ) and insert it in the differential.

Fig 1: Inserting Adjusting Tool VW521/4 And VW521/13 Into Differential
GWWA39-10566Courtesy of AUDI OF AMERICA, LLC

-- Turn the differential five turns in both directions so that the bearings settle.

-- Attach the Dial Gauge Holder: VW387  -6- to the final drive cover -arrow-

GWWA39-10967Courtesy of AUDI OF AMERICA, LLC
  1. Dial Indicator: VAS6080A 
  2. Dial Gauge Extension (8 cm plan)
  3. Measuring Lever: VW388 
  4. Ring Gear Locking Sleeve: VW521/4 
  5. Positioning Tolerance Shell: VW521/13 
  6. Dial Indicator Holder: VW387 

-- Insert the Dial Gauge for example : VAS6080A  using the Dial Gauge Extension (8 cm plan).

-- Adjust the Measuring Lever: VW388  to the dimension -a- = 79 mm (for the ring gear 196 mm).

So that an exact torsional backlash can be measured, the pinion must be locked.

GWWA34-11420Courtesy of AUDI OF AMERICA, LLC

-- To do so remove the transmission cover. Refer to OVERVIEW - TRANSMISSION COVER .

-- Insert the Drive Axle Wedge Tool : T10161  between the output gear -1- for the drive gear and transmission housing.

Determine the play between the tooth flanks as follows:

-- Turn ring gear until it makes contact with a tooth flank (end of backlash travel).

-- Set the dial gauge to "0" with 2 mm pretension.

-- Turn ring gear back until lying against an opposite tooth flank (backlash).

-- Read the torsional backlash and write down the measured value.

-- Turn the ring gear 90° and repeat measurements three more times. To continue turning, remove the Drive Axle Wedge Tool: T10161  from between the output gear for the drive gear and the transmission housing. Refer to Torsional Backlash, Measuring => Insert the Drive Axle Wedge Tool: T10161 between the output gear -1- for the drive gear and transmission housing. .

Average Torsional Backlash, Determining

-- Add the four measured values and then divide the total by 4.

Example:  
  1. Measured value 0.23 mm
+ 2. Measured value 0.24 mm
+ 3. Measured value 0.22 mm
+ 4. Measured value 0.23 mm
= Total of the measured values 0.92 mm

Shim Thickness "S2 ", Determining

Formula: "S2 " = "S2 *" - measured torsional backlash + specified torsional backlash

Example:  
  Old shim "S 2 *" 1.05 mm
- Measured average torsional backlash 0.23 mm
+ Specified torsional backlash (desired average value for the torsional backlash) 0.15 mm
= Shim thickness "S 2 " 0.97 mm

Available shims "S 2 " Adjusting Shims Available for ; for the part number. Refer to the Parts Information.

Shim Thickness "S 1 ", Determining

Formula: "S 1 " = "S total " - "S 2 "

Example:  
  Total shim thickness "S total " for "S 1 *" + "S 2 *" 2.26 mm
- Shim thickness "S 2 " 0.97 mm
= Shim thickness "S 1 " 1.29 mm

Available shims "S 1 " Adjusting Shims Available for ; for the part number. Refer to the Parts Information.

-- Remove the old shims "S 1 *" and "S 2 *" and install the newly determined shims. Refer to OVERVIEW - DIFFERENTIAL .

Measurement Check

GWWA39-10967Courtesy of AUDI OF AMERICA, LLC

-- Turn the differential five turns in both directions after installing the shims "S 1 " and "S 2 " so that the tapered roller bearings can settle.

-- Measure backlash on the circumference four times.

  1. Dial Indicator: VAS6080A 
  2. Dial Gauge Extension (8 cm plan)
  3. Measuring Lever: VW388 
  4. Ring Gear Locking Sleeve: VW521/4 
  5. Positioning Tolerance Shell: VW521/13 
  6. Dial Indicator Holder: VW387