Audi Workshop Service and Repair Manuals

Re-determining thickness of shim “S4” This adjustment is necessary when the following components are renewed: t  Bearing plate t  Inner race for 1st speed selector gear needle bearing t  Synchronising hub for 1st and 2nd gear t  Inner race for 2nd speed selector gear needle bearing t  3rd gear wheel t  Spacer sleeve t  4th gear wheel The procedure restores the required preload of the tapered roller bearings for the pinion shaft.

1 -	Bearing plate

2 -

Shim “S4”

3 -	Needle bearing inner race for 1st speed selector gear

4 -	Synchronising hub for 1st and 2nd gear

5 -	Needle bearing inner race for 2nd speed selector gear

6 -	3rd gear wheel

7 -	Spacer sleeve

8 -	4th gear wheel

9 -	Pinion shaft

When renewing the pinion shaft (final drive set), observe table of adjustments → .

a -	Bearing plate housing depth

b -	Length of needle bearing inner race for 1st speed selector gear

c -	Length of centre of synchronising hub for 1st and 2nd gears

d -	Length of needle bearing inner race for 2nd speed selector gear

e -	Length of 3rd gear wheel

f -	Length of spacer sleeve

g -	Length of 4th gear wheel

S4 -	Thickness of shim “S4”

1.) Determining thickness of shim when renewing bearing plate –  Use a digital depth gauge. –  Measure difference of depth -a- on old and new bearing plates.

Example:
Depth -a- (old bearing plate)	124.40 mm
Depth -a- (new bearing plate)	124.65 mm
Difference	= 0.25 mm

l  If the new bearing plate is deeper, install a thicker “S4” shim. l  If the old bearing plate is deeper, install a thinner “S4” shim.

Example:
Previous “S4” shim	0.95 mm
Difference	+ 0.25 mm
New “S4” shim	= 1.20 mm

Shims available → Anchor.

2.) Determining thickness of shim when renewing needle bearing for 1st gear –  Use a digital depth gauge. –  Measure length -b- on both old and new needle bearing inner races.

Example:
Length -b- on old inner race	33.35 mm
Length -b- on new inner race	33.40 mm
Difference	= 0.05 mm

l  If the old inner race is longer, install a thicker “S4”shim. l  If the old inner race is shorter, install a thinner “S4”shim. Table of shims → Anchor. 3.) Determining thickness of shim when renewing components → Item to → Item –  Use a digital depth gauge. –  Determine difference in dimensions between old and new component in the same manner. t  Length of centre of synchronising hub → Item for 1st and 2nd gears ( → Item). t  Length of needle bearing inner race → Item for 2nd speed selector gear ( → Item). t  Length → Item of 3rd gear wheel ( → Item). t  Length → Item of spacer sleeve ( → Item). t  Length → Item of 4th gear wheel ( → Item). Table of shims → Anchor. Available shims for “S4” –  Select thickness of required shim(s) from following table:

Available shims - Thickness of shims in mm 1)2)
0.45	0.65	0.85
0.50	0.70	0.90
0.55	0.75
0.60	0.80
l  1) Part numbers → Parts catalogue. l  2) The exact shim thickness required can be obtained by using the shim tolerance variations. Install two shims if necessary.