Measuring backlash — AUDI

🧭 Before you start

Fits: Audi A4 Cabriolet B6/B7 (8H), Audi A4 B6/B7 (8E), Audi A6 C6 (4F, 2004–2011)

• Special tools named: dial gauge
• Renewed: final drive gear set
• Also covered elsewhere: Electronic parts catalogue

Don't miss

• If the pinion shaft (1) rotates during the measurements, counter-hold pinion shaft to make sure that the measured value of the backlash is correct.
• After installing shims "„S"1“ and "„S"2“, turn differential 5 turns in both directions so that the tapered roller bearings settle.

🔩 Torque settings

Values can differ between engine variants — check the code stamped on your block.

ℹ️ Always cross-check the exact figure against your vehicle's factory manual before final tightening — a wrong torque can damage the engine. These values are extracted from workshop data and may not cover every variant or revision.

📋 Procedure

1. Install differential with crown wheel: "„S"1“ is fitted on cover side, "„S"2“ in gearbox housing.
2. Fit cover for final drive and tighten bolts to 24 Nm. — 24 Nm (18 lb-ft)
3. Insert crown wheel adjusting toolVW 521/4 and VW 521/8.
4. Turn differential 5 turns in both directions to settle tapered roller bearings.
5. Secure universal dial gauge bracketVW 387 to gearbox housing.

6. Fit dial gauge with dial gauge extensionVW 382/10 (6 mm flat).
7. Adjust measuring leverVW 388 to distance "„a“" = 75 mm (for ∅ 186 mm crown wheel).
8. Measure play between teeth faces (backlash) as follows:
9. Turn crown wheel until it makes contact with the face of one tooth (end of backlash travel).
10. Preload dial gauge to 2 mm and set to "„0“".
11. Turn back crown wheel until it makes contact with opposite tooth face (backlash).
12. Take backlash reading and note down measured value.
13. Turn crown wheel through 90° and repeat measurements a further 3 times. [Note: If the pinion shaft (1) rotates during the measurements, counter-hold pinion shaft to make sure that the measured value of the backlash is correct.]
14. Add the four measured values together and divide by four. [Note: If the individual measurements differ by more than 0.06 mm, this means that the installation of the crown wheel is not correct or that the final drive gear set itself is defective. Check the installation; renew the final drive gear set if necessary.]
15. Determine shim(s) according to table. For part numbers, refer to Electronic parts catalogue.
16. Determine shim(s) according to table. For part numbers, refer to Electronic parts catalogue.
17. After installing shims "„S"1“ and "„S"2“, turn differential 5 turns in both directions so that the tapered roller bearings settle.
18. Measure backlash four times on circumference. [Note: If the pinion shaft (1) rotates during the measurements, counter-hold pinion shaft to make sure that the measured value of the backlash is correct.Adjustment must be repeated if backlash is outside tolerance. The total shim thickness "„S"total“ must remain unchanged.The discrepancy between individual measured values must not exceed 0.06 mm.]

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