Audi Workshop Service and Repair Manuals

Setting reverse gear clutch Special tools and workshop equipment required

t  Digital depth gauge -VAS 6087- t  Digital caliper, 150 mm -VAS 6335- t  2 rulers -T40100- t  Clean, flat measurement surface, e.g. compressor tool -T10285-

Setting of reverse gear clutch by determining shims:   Note t  Heed the general repair instructions → Chapter. t  Rules for cleanliness when working on automatic gearbox → Chapter. Conditions: l  Thoroughly clean all components prior to insertion. l  Gearbox removed and attached in vertical position to repair stand → Anchor. l  Reverse gear clutch with corrugated washer removed → Chapter.   Note The purpose of the following measurements is to determine the upper -5- and lower -2- shims for setting the reverse gear clutch. l  To ensure accuracy, all tool and component surfaces must be absolutely clean when performing the following measurements.

1. Measurement from sealing surface of input shaft to contact surface of corrugated washer, determination of dimension -B-: –  Clean the contact and sealing surfaces at the gearbox housing. Completely remove any seal remnants. –  Use the digital depth gauge -VAS 6087- to take measurement from the sealing surface of the input shaft to the contact surface of the corrugated washer in the gearbox housing. –  Note down the measured value -B-. –  Repeat the measurement at two other offset points and note down the measured values. –  Determine the mean value MB from the 3 measured values and note down.    Mean value MB =  Messwert B1 + B2 + B3 3 Example:    Mean value MB =  38,15 mm + 38,14 mm + 38,14 mm 3  = 38.143 mm

2. Measurement of compressed clutch assembly, determination of dimension -A-:   Note For measurement, the corrugated washer -2- is inserted beneath the clutch pack. l  Use a clean, flat measurement surface -1- as a base. The following description is based on use of the compressor tool -T10285-.

–  Start by placing the corrugated washer -A- on the measurement surface -1-. –  Then alternately fit the friction plates -C- (6x) and the outer plates -B- (5x) one at a time on the corrugated washer (always facing in the same direction).

–  Precisely align all the plates on top of one another. –  Place the two rulers -T40100- over the clutch pack.   Note The weight of the rulers -T40100- presses the air out of the plates and exerts the specified 2.5 kg load on (compresses) the corrugated washer. –  Use the digital depth gauge -VAS 6087- to take measurement to the working surface -1- and note down the measured value -a-. l  When taking measurements, the digital depth gauge -VAS 6087- must make flush contact with both rulers -T40100-. –  Repeat the measurement on the opposite side of the clutch pack and note down measured value 2. –  Move the 2 rulers -T40100- by 90°. –  Repeat the measurements and note down measured values 3 and 4. –  Determine the mean value Ma from the 4 measured values and note down.    Mean value Ma =  Messwert a1 + a2 + a3 + a4 4

Determination of dimension -A-: –  Measure and note down the thickness -b- of the rulers -T40100-. Dertermination of height of compressed clutch assembly:    Dimension -A- = Mean value Ma - -b- –  Note down dimension -A- of the compressed clutch assembly. Example: Already determined: Mean value MB = 38.143 mm Thickness -b- of rulers -T40100- = 7.47 mm    Dimension -A- = Mean value MB - -b- = 38.143 mm - 7.47 mm = 27.98 mm

3. Measurement from sealing surface of input shaft to piston of reverse gear clutch, determination of dimension -C-:

–  Place a clean outer plate -1- on the input shaft removed.   Note The causes the outer plate -1- to come to rest on the piston of the reverse gear clutch. Correct measurement to the highest point of the piston can be performed by way of the flat outer plate. The thickness -d- of the outer plate -1- is subsequently subtracted again for determination of the height of the piston.

–  Use the digital depth gauge -VAS 6087- to take measurement to the sealing surface of the input shaft and note down the measured value -D-. –  Repeat the measurement at 2 other offset points and note down the measured values. –  Determine the mean value MD from the 3 measured values and note down. Mean value:    Mean value MD =  Messwert D1 + D2 + D3 3

–  Remove the outer plate fitted from the input shaft and measure and note down the thickness -d-.

Calculation of dimension -C- from sealing surface of input shaft to piston of reverse gear clutch:    -C- = Mean value MD - Thickness -d- of outer plate fitted -1- –  Note down dimension -C-.

Example
	Mean value MD =  5,11 mm + 5,10 mm + 5,12 mm 3	5.11 mm
-	Thickness -d- of outer plate -1- fitted	– 2.13 mm
=	Dimension -C- from sealing surface of input shaft to piston of reverse gear clutch	= 2.98 mm

4. Determination of thickness “E” of both shims: –  Use the following calculation method to determine the thickness of the shims:

Determination of shims for reverse gear clutch Clearance at least 3.0  + -  0.2 mm with 2.5 kg load ( → Anchor)		Determined and fixed measured values
Measurement from sealing surface of input shaft to contact surface of corrugated washer in gearbox		Mean value MB
Thickness of input shaft seal at gearbox housing	+	0.27 mm
Measurement from sealing surface of input shaft to piston of reverse gear clutch	-	Dimension “C”
Measurement of compressed clutch assembly	-	Dimension “A”
Minimum clearance	-	3.0 mm
Calculated thickness of both shims	=	“E”
l  The weight of the 2 rulers -T40100- when measuring the clutch assembly produces the specified load of 2.5 kg on the clutch assembly. l  The thickness of the lower shim “E1” must be at least 2.15 mm.

Determination:    “E” = MB + 0.27 mm - “C” - “A” - 3.0 mm –  On the basis of the calculated value “E”, select the thickness “E1” of the lower shim as per Table 1 → Anchor. –  Calculation of dimension “M2” for determining upper shim:    “M2” = “E” - Thickness “E1” of lower shim selected –  On the basis of the dimension “M2”, select the thickness “E2” of the upper shim as per Table 2 → Anchor.   Note Assign the shims by way of the → Electronic parts catalogue.

–  Measure and note down the thicknesses of the two shims selected.   Note On account of their tolerances, the actual thicknesses of the shims may differ slightly. –  Add together the thicknesses of the two shims measured and note down the value.    Thickness “E1 measured” + Thickness “E2 measured” = Thickness “Emeasured”   Caution Risk of starting problems after re-installing the gearbox. The thickness of the two shims selected must be less than the calculated dimension “E”. Calculation check: l  (Thickness “E1 measured” + Thickness “E2 measured”)  = Thickness “Emeasured” l  Thickness “Emeasured” must be less than thickness “E” –  Fit the reverse gear clutch with the shims selected → Chapter.

Table 1 Determination of lower shim	Thickness “E1” of lower shim selected
“E” Measuring range in (mm)	Thickness (mm) + - 0.03
3,925 ... 4,174	2,15
4,175 ... 4,424	2,15
4,425 ... 4,674	2,65
4,675 ...4,924	2,9
4,925 ... 5,174	3,15
5,175 ...5,424	3,15
5,425 ... 5,674	2,65
5,675 ... 5,924	2,9
5,925 ... 6,174	3,15
6,175 ... 6,400	3,15

Table 2 Determination of upper shim	Thickness “E2” of upper shim selected
Dimension “M2” = “E” - Selected lower shim “E1” Measuring range in (mm)	Thickness (mm) + - 0.03
1,829 ... 2,024	1,9
2,025 ... 2,324	2,15
2,725 ... 2,774	2,65
2,775 ... 3,024	2,9
3,025 ... 3,120	3,15

Example: The example is based on the following values: t  Mean value MB = 38.143 mm t  “A” = 27.98 mm t  “C” = 2.98 mm    “E” = MB + 0.27 mm - “C” - “A” - 3.0 mm    “E” = 38.143 mm + 0.27 mm - 2.98 mm - 27.98 mm - 3.0 mm = 4.453 mm –  Determination of lower shim (thickness “E1”) from Table 1:    Thickness “E1” = 2.65 mm –  Calculation of dimension “M2” for determining upper shim:    “M2” = “E” - Thickness “E1” of lower shim selected    “M2” = 4.453 mm - 2.65 mm = 1.803 mm –  Determination of upper shim (thickness “E2”) from Table 2:    Thickness “E2” = “not possible” l  As the value 1.803 mm in this example is outside the selectable measuring ranges in Table 2 (upper shim → Anchor), the next thinnest lower shim “E1” must be selected from Table 1 (lower shim → Anchor). –  Selection of thickness “E1” of next thinnest lower shim from Table 1:    Thickness “E1” = 2.15 mm –  Calculation of dimension “M2” for determining upper shim (thickness “E2”):    “M2” = “E” - Thickness “E1” of lower shim selected    “M2” = 4.453 mm - 2.15 mm = 2.303 mm –  Determination of upper shim (thickness “E2”) from Table 2:    “E2” = 2.15 mm

–  Measure and note down the thicknesses of the two shims selected.   Note On account of their tolerances, the actual thicknesses of the shims may differ slightly. –  Add together and note down the thicknesses of the two measured shims.    “E1 measured” + “E2 measured” = “Emeasured”   Caution Risk of starting problems after re-installing the gearbox. The thickness of the two shims must be less than the calculated dimension “E”. Calculation check: l  (Thickness “E1 measured” + Thickness “E2 measured”)  = Thickness “Emeasured” l  Thickness “Emeasured” must be less than thickness “E” The following values were determined in the example: t  “E1” = 2.15 mm t  “E2” = 2.15 mm t  “E” = 4.453 mm    (“E1” + “E2”) < “E”    (2.15 mm + 2.15 mm) = 4.3 mm < 4.453 mm The shims have been correctly selected for this example –  The reverse gear clutch can be fitted.