Final Drive, Adjusting, When Replacing The Transmission Housing Or Pinion

Special tools and workshop equipment required

Dial Indicator : VAS 6080A
Ring Gear Locking Sleeve : VW 521/4
: VW 521/5
Ring Gear Locking Sleeve :VW521/4
Crown Wheel Adjusting Tool :VW 521
Crown Wheel Adjusting Tool :VW 521
Positioning Tolerance Shell :VW521/13
Clamping Piece :VW386A
Clamping Piece : VW 386A
Measuring Lever :VW388
Measuring Set - Magnetic Plate - 50mm :VW 385/17
Dial Gauge
Dial Gauge Extension
Dial Indicator Holder :VW 387

Careful adjustment is important for service life and smoothness of the final drive.
If only the differential bearing or the differential is replaced, the pinion can remain installed. Then perform the procedure. Refer to FINAL DRIVE, ADJUSTING WHEN REPLACING DIFFERENTIAL OR DIFFERENTIAL BEARING .
Adjustment overview. Refer to Adjustment Overview - Final Drive .
A new adjustment of the final drive is required, if the transmission housing or the pinion were replaced.

Pre-work

-- Remove the flywheel. Refer to Flywheel, Removing and Installing .

-- Remove the right flange shaft. Refer to Right Flange Shaft, Removing and Installing .

-- Remove the pinion. Refer to Pinion, Removing and Installing .

-- Remove the flange shafts seals. Refer to Right Seal, Replacing .

The total shim thickness S_total for the shims S₁ + S₂ , determining

For the initial measurement, temporary shims with a determined thickness (in the example S₂ =0.65 mm, S₁ = 1.05 mm) are inserted. They are designated as S₁ * and S₂ * in the following. After determining the torsional backlash, they are replaced by the final shims.

-- Remove the bearing outer race for the differential from the transmission housing and the final drive cover and remove the shims. Refer to Overview - Differential .

-- Drive in the left outer race/tapered roller bearing together with shim S₂ (0.65 mm) into the transmission housing.

Fig 1: Driving Outer Race For Tapered Roller Bearing With Shim Into Transmission Housing

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-- Install the outer race for the right angular contact ball bearing with the temporary shim S₁ * (1.05 mm) in the final drive cover.

Fig 2: Identifying Outer Race Tapered Bearing, Installation

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The larger diameter of the Seal Installer - Crankshaft VW 204B points to the outer race for the angular contact ball bearing.

-- Insert the differential into the transmission housing. The ring gear is laying on the right side in front of the final drive cover.

Conditions

O-ring is inserted in final drive cover.

-- Fasten the final drive cover carefully with four bolts diagonally to 20 Nm.

-- Turn the transmission so that the final drive cover faces upward.

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

-- Place the Measuring Set - Magnetic Plate - 50mm : VW 385/17 on the differential.

Fig 3: Installing Magnetic Plate 50MM Dia. VW 385/17 And Dial Gauge

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-- Attach the measuring tools to the transmission housing.

-- Set the dial gauge (3 mm measuring range) -A- to "0" with 2 mm pre-tension.

-- Position the dial gauge test probe on the differential.

-- Lift the differential without turning it, read backlash on dial indicator and note.

Measured value in the following example: 0.22 mm

-- To lift the differential, secure the special tools Crown Wheel Adjusting Tool Ring Gear Locking Sleeve :VW 521/4 and :VW 521/5 left on the differential (housing side).

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-- At the same time the Crown Wheel Adjusting Tool :VW 521 must not touch the transmission housing -arrow-.

-- If measurement is repeated, differential must first be rotated five turns in both directions again to seat the bearing.

-- Formula: S total = S₁ * + S₂ * + measured value + bearing pre-load

Example:
	Inserted shims "S ₁ " + "S ₂ "	1.70 mm
+	Measured value	0.22 mm
+	Bearing pre-load (constant value)	0.30 mm
=	Total shim thickness "S _total " for "S ₁ " + "S ₂ "	2.22 mm

Conditions

The temporary shim S ₁ * with a thickness of 1.05 mm remains installed in the final drive cover.

Determining the following shim thickness S ₂ *

-- Formula: S₂ * = S_total - S₁ *

Conditions

The temporary shim S ₂ * is replaced by the final shim S ₂ after the torsional backlash has been determined.
Total shim thickness S_total. remains unchanged.

Example:
	Total shim thickness S_total for S₁ + S₂	2.22 mm
-	Inserted shim S₁ *	1.05 mm
=	Shim thickness S₂ *	1.17 mm

Torsional Backlash, Measuring

Conditions

The pinion is installed with shims "S₃ " and "S₄ ".
The spur gear unit output gear is removed.
O-ring is inserted in final drive cover.

-- Install the differential with shim: "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.

Fig 4: Inserting Adjusting Tool VW521/4 And VW521/13 Into Differential

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Tip

Check the torsional backlash when tightening the final drive cover. Some play must always be present.
The play can be checked on the pinion by turning back and forth.

-- Complete the Crown Wheel Adjusting Tool :VW 521 and insert it in the differential.

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

-- Attach the Dial Gauge Holder : VW 387 -6- to the final drive cover -arrow-

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Dial Indicator :VAS 6080A
Dial Gauge Extension (8 cm plan)
Measuring Lever :VW388
Ring Gear Locking Sleeve :VW521/4
Positioning Tolerance Shell :VW521/13
Dial Indicator Holder :VW 387

-- Insert the Dial Gauge for example Dial Indicator : VAS 6080A using the Dial Gauge Extension (8 cm plan).

-- Adjust the Measuring Lever :VW 388 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.

-- To do so remove the bolt -1-.

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-- Place on the threaded hole washer or with a nut (for example M12) -2-.

Conditions

The dimension -a- must be at least 14 mm.

Locking the pinion

-- Place on the threaded hole washer or with a nut (for example M12) -2-.

Fig 5: Locking the Pinion -1-

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Conditions

The dimension -a- must be at least 14 mm.

2 - M8 x 110 Bolt or M8 x 130 Threaded Rod with M8 Nut
3 - Clamping Piece :VW386A

-- Lock the pinion -1- with the bolt -arrow- from the Clamping Piece :VW 386A .

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. Loosen the Clamping Piece :VW 386A to additionally tighten.

Average Torsional Backlash, Determining

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

Example:
	1. Measured value	0.55 mm
+	2. Measured value	0.54 mm
+	3. Measured value	0.55 mm
+	4. Measured value	0.56 mm
=	Total of the measured values	2.20 mm

Conditions

Results: the average torsional backlash is approximately 2.20 mm: 4 = 0.5 mm

Determining the thickness of the shim S₂

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

Example:
	Old shim S₂ *	1.17 mm
-	Measured average torsional backlash	0.55 mm
+	Specified torsional backlash (desired average value for the torsional backlash)	0.15 mm
=	Shim thickness S₂	0.77 mm

Shim thickness S₂ (mm)
0.37	0.65	0.93	1.21	1.49
0.41	0.69	0.97	1.25	1.53
0.45	0.73	1.01	1.29	1.57
0.49	0.77	1.05	1.33	1.61
0.53	0.81	1.09	1.37	1.65
0.57	0.85	1.13	1.41
0.61	0.89	1.17	1.45

Determining the thickness of the shim S₁

-- Formula: S₁ = S_total - S₂

Example:
	Total shim thickness S_total for S₁ + S₂	2.22 mm
-	Shim thickness S₂	0.77 mm
=	Adjusting shim S₁ thickness	1.45 mm

Shim thickness S₁ (mm)
0.65	0.89	1.13	1.37	1.61
0.69	0.93	1.17	1.41	1.65
0.73	0.97	1.21	1.45	1.69
0.77	1.01	1.25	1.49	1.73
0.81	1.05	1.29	1.53	1.77
0.85	1.09	1.33	1.57

-- Remove the old shims S₁ * and S₂ * and install new determined shims.

Measurement check

-- 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.

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-- Measure backlash on the circumference four times.

Specified value: 0.15 ± 0.04 mm

Dial Indicator :VAS 6080A
Dial Gauge Extension (8 cm plan)
Measuring Lever :VW388
Ring Gear Locking Sleeve :VW521/4
Positioning Tolerance Shell :VW521/13
Dial Indicator Holder :VW 387

Conditions

If the torsional backlash is outside of the tolerance, then repeat the adjustment. Total shim thickness "S _total " may not be changed.