Audi Workshop Service and Repair Manuals

ATF supply unit

Caution Make sure to install ATF pump and ATF supply unit of same version - oil drillings must align. The ATF pump will not build up pressure if other version of ATF supply unit is fitted.

2 -	Corrugated washer

q	Check for distortion

4 -	ATF pump housing

q	Check running surfaces for scoring and signs of abnormal wear → Fig.

q	Check brass bush for wear → Fig.

5 -

Annulus

q	Check running surfaces for scoring and signs of abnormal wear → Fig.

6 -	ATF pump gear

q	Check running surfaces for scoring and signs of abnormal wear → Fig.

q	Check drive lugs in ATF pump gear → Fig.

8 -	Intermediate plate

q	Check running surfaces for scoring and signs of abnormal wear → Fig.

10 -	ATF supply unit

q	Check that flow control valve of ATF supply unit moves freely → Fig.

14 -	Stator shaft

q	Check brass bushes for wear → Fig.

q	Check splines for wear

q	Must be seated securely in housing of ATF supply unit → Item; renew both parts if loose

16 -	Rectangular section seals for clutch “B”

q	Checking for wear → Fig.

17 -	Rectangular section seal for clutch “A”

q	Checking for wear → Fig.

18 -	Axial needle bearing

q	Perform visual check for damage: axial needle bearing and contact surfaces should be in as-new condition; renew if necessary.

Checking brass bush in ATF pump housing for wear. –  Check running surface of brass bush -arrow- for wear. l  The running surface should not have any deep scoring and/or blue discoloration. If there are deep scores and/or blue discolouring: –  Renew ATF pump. Proceed as follows if the running surface has no blue discoloration and there are only slight scores: –  Rub down running surface one or two times with abrasive paper and oil (grain size 600). –  Clean running surface thoroughly with clean cloth and check running surface. l  The running surface should now be in as-new condition. If scoring is still present after this step: –  Renew ATF pump.

–  Also check hub -arrow- of torque converter for scoring. If scoring is visible on the torque converter: –  Renew torque converter.

Checking components of ATF pump for scoring and signs of wear –  Check running surfaces of following components for scoring and signs of wear: 2 -  ATF pump housing 3 -  Annulus (outer pump gear) 4 -  ATF pump gear 5 -  Intermediate plate l  The running surfaces should have either a dull or bright finish and should be free of even the slightest trace of scoring.   Note A defective ATF pump causes delays in power transmission and gear changes.

Checking drive lugs in ATF pump gear –  Check whether the drive lugs -arrows- on the ATF pump gear show signs of damage or are broken off; renew ATF pump if necessary. Possible causes of fault: A -  Torque converter not fully inserted when installing gearbox or engine B -  Centring sleeve for torque converter not fitted in crankshaft   Caution Make sure that broken-off drive lugs are found and removed.

Checking flow control valve in ATF supply unit Check flow control valve as follows: –  Move valve piston against spring pressure. l  The valve piston should move freely in both directions -arrow-. l  The valve should be free of scoring. l  There must be no metal particles lodged in aperture -1-.   Note Power transmission may fail completely if the valve piston sticks or if aperture -1- is obstructed.

Checking brass bushes on stator shaft for wear. –  Check running surfaces of brass bushes -arrows- on inside of stator shaft for wear. l  The running surfaces should not have any deep scoring and/or blue discoloration. If there are deep scores and/or blue discolouring: –  Renew stator shaft. Proceed as follows if the running surfaces have no blue discoloration and there is only slight scoring: –  Rub down running surface one or two times with abrasive paper and oil (grain size 600). –  Clean running surface thoroughly with clean cloth and check running surface. l  The running surfaces should now be in as-new condition. If scoring is still present after this step: –  Renew stator shaft.

Checking rectangular section seals -item 16- for wear   Note Always renew rectangular section seals. Nevertheless, the wear pattern on the rectangular section seals gives an indication of the condition of the contact surface for the seals. For this reason it is always advisable to check the rectangular section seals for wear. If the axial wear on the rectangular section seals exceeds 0.3 mm -arrow 1- (slight wear on the outside corners is normal): –  Renew stator shaft. If the radial wear on the rectangular section seals exceeds 0.3 mm -arrow 2- (compare with thickness of new rectangular section seal): –  Renew cylinder “B” → Item.

Checking rectangular section seal -item 17- for wear   Note Always renew the rectangular section seal. Nevertheless, the wear pattern on the rectangular section seal gives an indication of the condition of the contact surface for the seal. For this reason it is always important to check the rectangular section seal for wear. If the axial wear on the rectangular section seal exceeds 0.3 mm -arrow 1- (slight wear on the outside corners is normal): –  Renew stator shaft. If the radial wear on the rectangular section seal exceeds 0.3 mm -arrow 2- (compare with thickness of new rectangular section seal): –  Renew cylinder “A” → Item.