LI27.00-P-067577 Service Bulletin/Repair Instructions

Leak on TRANSMISSION 725.0 (9G

TRONIC) BR166/292/167 with 4MATIC

Topic number
LI27.00-P-067577
Version
2
Function group
27.00 General
Date
07-20-2020
Validity
Leak on TRANSMISSION 725.0 in BR166/292/167 with

4MATIC
Reason for change
Addition of inspection method for when leak is visible in

area of radial shaft sealing ring
Reason for block
Complaint:
Leakage on transmission 725.0 (9G TRONIC) in area of transfer case/adapter housing.

If leakages are detected on the TRANSMISSION 725.0 (9G TRONIC), work through the tests with any remedial measures.
Attachments

File
Description
Öl im Bereich RWDR am Getriebe 725.0.jpg
Oil in radial shaft sealing ring area on transmission 725.0
Öl im Rundflansch am Getriebe 725.0.jpg
Oil in round flange on transmission 725.0
Cause:
- Tightening torque on collar nut (output shaft)

- Leakage on transfer case

- Leakage at radial shaft sealing ring (RSS)
Remedy:
Localize leakage by checking oil. For better differentiation of the oil, drops should be placed onto a white sheet of paper:

- Gold-yellow oil leaks from transmission 725.0 (9G TRONIC)

- Red oil leaks from the transfer case

If gold-yellow oil detected: Check if oil is visible on round flange/collar nut:

If oil is visible on round flange:

1. Assess caulking of collar nut and determine release torque of collar nut

07-20-2020 7:29 PM

© Copyright Mercedes-Benz AG
KATSELF
Page 1/3
2. Replace collar nut (B) and round flange (A), clean everything beforehand

3. Tighten new collar nut to 220 ± 20 Nm (initial tightening torque), then release collar nut by 30°, finally tighten collar

nut again to 200 ± 20 Nm (second tightening torque)

4. Caulk new collar nut according to specification

5. Specify damage code 27332 38.

If oil is visible in area of radial shaft sealing ring (RSS):

1. Remove RSS

2. Check position of retaining ring opening

3. If necessary, use retaining ring pliers (see picture "Retaining ring pliers.jpg") to turn it to the "7 o'clock position" (see

example picture "Verdrehen auf 7Uhr_Turn to 7oclock.jpg")

*Note: The ventilation hole on the housing must not be covered by the retaining ring.

4. Replace the RSS; coat the new RSS with transmission oil and press in using the special tool; observe AR27.40p-0206EWM

5. Clean everything beforehand and replace collar nut (B) and round flange (A)

6. Tighten new collar nut to 220 ± 20 Nm (initial tightening torque), then release collar nut by 30°, finally tighten collar

nut again to 200 ± 20 Nm (second tightening torque)

7. Caulk new collar nut according to specification

8. Specify damage code 27311 04.

For red oil:

Repair transfer case in accordance with WIS specification and assign corresponding damage code.
Attachments

File
Description
Verdrehen auf 7Uhr_Turn to 7oclock.jpg
If necessary, use retaining ring pliers (see picture "Retaining ring pliers.jpg") to turn it to the "7 o'clock position" (see example picture "Turn to 7oclock.jpg")

*Note: The ventilation hole on the housing must not be

covered
Symptoms

Power transmission / Automatic transmission / Leakage / Leaks
Parts

Attachments

File
Description
Bundmutter (B) und Rundflansch (A) am GETRIEBE 725. Collar nut (B) and round flange (A) on TRANSMISSION

0.JPG

725.0.

07-20-2020 7:29 PM

© Copyright Mercedes-Benz AG
KATSELF
Page 2/3
Sicherinsring Zange.jpg
Werkzeug/Tooling: Retaining ring pliers
Operation numbers/damage codes

Op. no.
Operation text
07-20-2020 7:29 PM

© Copyright Mercedes-Benz AG
Time
KATSELF
Damage

code
Note
27332 38
Bolt/nut for output flange for automatic transmission loose
27311 04
Radial shaft sealing ring on transmission housing at rear leaky
Page 3/3

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