7G-DCT: Scratching noise when changing gear from D to R with transmission cold.
Topic number

LI27.50-P-064440

Version

6

Function group

27.50 Gear assembly

Date

02-02-2018

Validity

All vehicles of BR 176, BR 117, BR 156, BR 242, BR 246
with transmission 724.0

Reason for change

Series production vehicles updated
Important information for repairs

Reason for block

Complaint:

Scratching noise when changing gear from D to R with the transmission cold.

Attachments
File

Description

Kratzen in R.mp3

Scratching in R at second 14

Cause:

Possibly Synchronizer ring of reverse gear
Check whether the vehicle is affected by the scratching noise:
Accelerate the cold vehicle to 30 km/h (2nd gear must be engaged).
Slow the vehicle with the brakes and at 7 km/h select reverse gear.

Remedy:
Information for repairs, valid for all vehicles:
•
•
•

Caution when removing the oil pump gear: The mounting nut has a left-hand thread. Do not use an impact
wrench or pneumatic tools, otherwise the shaft of the primary oil pump and the special tool will be damaged.
Assembly: Before installing the oil pump gear, the shaft of the primary oil pump and the contact surface between
the nut and the pump gear must be cleaned of all grease and oil.
It is not absolutely necessary to remove the oil pump when replacing the output shaft.

AMG vehicles:

Remedy for 724.015 (prior to facelift):
02-02-2018 10:11 PM
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•

Order output shaft (3rd, 6th, 7th and reverse gear) A 246 260 95 00 with Index 28 and replace. Make sure that
the oil restrictors (A 246 372 18 50) are installed in the output shaft; if not, order them at the same time. When
assembling the transmission, make sure that the shift valve 56 (absolute pressure valve) in picture B for the park
pawl (AR27.10-P-0510NKB) is installed correctly. If the valve is installed the wrong way round, the park pawl will
be damaged due to pressure spikes.

•

Valid for transmission variants:
•
Transmission A 246 370 63 02 (FBS3 + VGS1)
•
Transmission A 246 370 57 02 (FBS3 + VGS2)
•
Transmission A 246 370 40 02 (FBS4 + VGS2)

Remedy for 724.016 (as of facelift):
•

Valid for transmission variant: A 246 370 54 03 (transmission without lock)
•
Order output shaft (3rd, 6th, 7th and reverse gear) A 246 260 27 01 with Index 28. Make sure that the oil
restrictors (A 246 372 18 50) are installed in the output shaft; if not, order them at the same time. When assembling the transmission, make sure that the shift valve 56 (absolute pressure valve) in picture B for the
park pawl (AR27.10-P-0510NKB) is installed correctly. If the valve is installed the wrong way round, the
park pawl will be damaged due to pressure spikes.

•

Until further notice, exchange the entire transmission for transmission variant A 246 370 70 03 (with lock, code
471, 37A). A special tool must first be created that makes it possible to rotate the differential under tension. The
current special tool does not fit in the lock.

Series production vehicles:

Remedy for vehicles , prior to 04/2017
•

Using the full VIN, check the part number of the output shaft (3rd, 6th, 7th and reverse gear) in the EPC. If one
of the following part numbers is listed, the output shaft must be replaced. Order the appropriate output shaft with
Index 28.

•

Output shafts:
- A 246 260 67 20
- A 246 260 68 20
- A 246 260 69 20
- A 246 260 70 20
- A 246 260 84 00
- A 246 260 85 00

•

If none of these part numbers is listed in the EPC, the transmission must be replaced in the event of complaints.

Symptoms
Power transmission / Automatic transmission / Function / Engaging process
Power transmission / Automatic transmission / Noises / General
Power transmission / Automatic transmission / Automatic transmission operation / Drive position selection / Noises /
Scratching
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Parts
Part number

ES1 ES2 Designation

Quantity Note

EPC

A 246 260 27 01

28

Output shaft

1

724.016

X

A 246 260 95 00

28

Output shaft

1

724.015

X

A 246 260 69 20

28

Output shaft

1

724.021,724.011, 724.004

X

A 246 260 70 20

28

Output shaft

1

724.001

X

A 246 260 68 20

28

Output shaft

1

724.002 with code A69 (Carbon synchronizer)

X

A 246 260 67 20

28

Output shaft

1

724.003 with code A69 (Carbon synchronizer), 724.020

X

A 246 260 85 00

28

Output shaft

1

724.003 with code 28A (Uprated synchronizer body) +A69 (Carbon synchronizer)

X

A 246 260 84 00

28

Output shaft

1

724.004, 724.011 with code 28A
(Uprated synchronizer body)

X

Operation numbers/damage codes
Op. no.

Operation text

Time

Damage
code

Note

27389 **

In the dealer text note please state
"Reverse gear scratching"

WIS-References
Document number

Title

Note

AR27.50-P-0560NKB

Disassemble/assemble output shaft

Allocation
Remedy

Validity
Vehicle

Engine

Transmission

A (176)

*

*

B (242, 246)

*

*

CLA (117)

*

*

GLA (156)

*

*

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