Determining total shim thickness "Stotal" for shims "S1" + "S2"

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(Setting preload of taper roller bearing for differential)

Drive pinion is removed!

NOTE: If only the taper roller bearings for the differential are being replaced, the ring gear can be removed from the differential housing. The pinion shaft does not need to be removed.

Pry out seals for flange shaft using a suitable lever.
Remove outer races of differential taper roller bearings and remove shims. Refer to Differential, disassembling and assembling
Drive outer race/taper roller bearing for left differential (housing side) with shim "S2*" of thickness 1.00 mm into housing. Refer to Differential, disassembling and assembling .

NOTE: For measurement purposes a shim "S2" with a thickness of 0.04 in is initially inserted. It is referred to as "S2*" in the following. After determining the backlash "S2*" will be replaced by the correct "S2".

Drive outer race/taper roller bearing for right differential (cover side) without shim in onto stop. Refer to Differential, disassembling and assembling .
Insert differential into housing. The ring gear is positioned on the right side (cover side).
Install cover and tighten bolts to 25 Nm.

Fig 1: Installing Special Tools VW 521/4 And 521/8 Onto Housing Side In Differential Housing

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Install special tools VW 521/4 and 521/8 onto housing side in differential housing.
Turn cover side of differential housing upward.
Turn differential 8 turns in both directions so that the taper roller bearings settle.
Place measuring plate VW 385/17 onto differential.

Fig 2: Installing Measuring Tools

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Install measuring tools.

A - Dial indicator extension approx. 30 mm long

B - Hex bolt M8 x 45

Position dial indicator extension in middle of measuring plate VW 385/17.
Set dial indicator (3 mm measuring range) to "0" with 2 mm preload.

Fig 3: Read Play On Dial Gauge

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Lift differential without turning; read off play on dial indicator and write it down.

Measurement in following example: 0.50 mm

If you want to repeat the measurement differential 8 turns in both directions so that the taper roller bearings settle.