LI27.50-P-064440 Service Bulletin/Repair Instructions

7G-DCT: Scratching noise when changing

gear from D to R when transmission cold.

Topic number
LI27.50-P-064440
Version
9
Function group
27.50 Gear assembly
Date
03-06-2020
Validity
All vehicles of BR 176, BR 117, BR 156, BR 242, BR 246

with transmission 724.0
Reason for change
Validity adapted
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:

•

•

•

•
The oil pump gear must be replaced at the same time, otherwise initial damage to the oil-pump drive shaft can

occur.

Caution when removing the oil pump gear: The mounting nut has a left-hand thread. Do not use an impact

wrench or compressed-air tool, 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.
03-06-2020 5:19 PM

© Copyright Mercedes-Benz AG
KATSELF
Page 1/3
AMG vehicles:
Remedy for 724.015 (prior to facelift):

•
Order and replace output shaft (3rd, 6th, 7th and reverse gear) A 246 260 95 00. 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):

•
Order output shaft (3rd, 6th, 7th and reverse gear) A 246 260 27 01. 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 variant:

•

A 246 370 54 03 (without lock)

•

A 246 370 70 03 (with lock, code 471, 37A) The special tool (SWZ) W724 589 00 16 00 for spinning and

calibrating the differential under preload is now available and can be ordered. It is no longer necessary to

replace the transmission. The adapter is then only to be inserted into the special tool W 724 589 02 31 00

in place of the driver in the current description. The function for spinning is identical to that already described. The WIS document is being amended.
Series production vehicles:
•
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 corresponding output shaft.
•
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.
03-06-2020 5:19 PM

© Copyright Mercedes-Benz AG
KATSELF
Page 2/3
Symptoms

Power transmission / Automatic transmission / Function / Engaging process

Power transmission / Automatic transmission / Drive position selection / Noises / Scratching

Power transmission / Automatic transmission / Noises / Noise
Parts

Part number
ES1 ES2 Designation
Quantity Note
EPC
A 246 260 27 01
Output shaft
1
724.016
X
A 246 260 95 00
Output shaft
1
724.015
X
A 246 260 69 20
Output shaft
1
724.021,724.011, 724.004
X
A 246 260 70 20
Output shaft
1
724.001
X
A 246 260 68 20
Output shaft
1
724.002 with code A69 (Carbon synchronization)
X
A 246 260 67 20
Output shaft
1
724.003 with code A69 (Carbon synchronizer), 724.020
X
A 246 260 85 00
Output shaft
1
724.003 with code 28A (Uprated synchronizer body) +A69 (Carbon synchronizer)
X
A 246 260 84 00
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
AR27.10-P-0510NKB
Disassemble/assemble

transmission
Note
Allocation

Remedy
Validity

Vehicle
Engine
Transmission
A (176)
*
*
B (242, 246)
*
*
CLA (117)
*
*
GLA (156)
*
*
03-06-2020 5:19 PM

© Copyright Mercedes-Benz AG
KATSELF
Page 3/3

SaleBestseller No. 1

TOPDON Bidirectional Scan Tool, 2026 New ArtiDiag900 Lite Automotive Diagnostic Tool for Full System, Scanner for Car with Active Test, 8 Reset, Wireless OBD2 Scanner Diagnostic Tool for All Vehicles

[2026 Top-Tier Hardware and Software Upgrade]: Topdon ArtiDiag900 Lite scanner has enhanced hardware and latest features, including Android 11.0, 5x faster CPU, 10000mAh battery for 12 hours of continuous operation, stable wireless diagnosis with Bluetooth 5.0, 8-inch touchscreen. Added bi-directional control, wireless diagnosis, battery testing (optional), and DTC repair guide
[TOPDON Bidirectional Scan Tool]: This bidirectional obd2 scanner sends commands to the vehicle's ECU for active testing, enabling users to accurately and quickly locate faulty components such as injectors, coolant pumps, windows, wipers, headlights, mirrors, etc. The bidirectional control scanner is the ideal choice for workshops/automotive repair shops as it significantly reduces mechanic's diagnostic time.
[Wireless Bluetooth Diagnostic Experience]: The AD900 Lite scan tool comes with a Bluetooth 5.0 VCI, supporting a wireless diagnostic range of up to 33 feet (10 meters), allowing you to diagnose without being confined to cables or tight spaces. Stable and fast wireless diagnosis provides a comfortable repair environment. It also offers VCI cables to increase connectivity options.
[DTC Repair Guide Function]: Easily diagnose issues with your vehicle and receive guidance on repairs with the topdon scan tool's fault code definitions for all systems,maximize your diagnostic capabilities. This function is compatible with Chrysler/Dodge/Jeep/Fiat 2010-2014 and expanding with continual updates,the AritDiag 900 Lite car diagnostic scanner is the must-have tool for any technician or DIY enthusiast.
[OE-Level Full System Diagnostics]:AritDiag900 Lite full system diagnostic scanner can scan ALL available modules(Engine, Transmission, Airbag, ABS, ESP, TPMS, Gateway, Steering, Radio, Air conditioning, ect.) to✔read ECU info, ✔read/clear codes, ✔view live data stream, ✔retrieves freeze-frame, ✔perform active tests, and more. With just a simple click, it provides you with accurate and in-depth diagnostics.

SaleBestseller No. 2

TOPDON ONE Bidirectional Scan Tool, 10.1" OBD2 Scanner with J2534 Pass-Thru and ECU Coding, Over 50 Resets, Topology Mapping Car Diagnostic Tool for All Vehicles

Dual WiFi & 10.1" Touchscreen: Provides a stable, high-speed wireless link 3x faster than bluetooth, and a responsive, professional interface. Topdon ONE obd2 scanner diagnostic tool ensures smooth, non-lagging diagnostic scan, boosting mechanic efficiency
J2534 Pass-Thru Support: The included ONE VCI supports the J2534 standard, allowing it to function as a pass-thru device when paired with OEM diagnostic software.Through TOPDON’s RLink platform, technicians can perform dealer-level coding, expanding in-house capabilities without investing in multiple factory automotive scan tools
OE Topology Mapping: Visualize the vehicle’s ECU network exactly as it’s built.Zoom, pan, and highlight specific modules to pinpoint component issues with precision.Topology mapping displays real-time communication between modules
Topfix AI Assistant: Covers 5 million plus fault codes and delivers instant causes, symptoms, and repair guidance with professional wiring diagrams for each code.Slashes diagnostic time, boosts first-time fix accuracy, and increases shop revenue
50 Plus Service Functions: Covers high-demand services like ADAS calibration, DPF regen, TPMS reset, ABS bleed, and throttle adaptation.Expands your service menu, allows you to charge premium rates, and turns away zero jobs due to lack of tooling. Vehicle-specific functionality may vary.

SaleBestseller No. 3

TOPDON TopScan Lite OBD2 Scanner Bluetooth, Bi-Directional Scanner Wireless All System Diagnostic Tool for iOS & Android, 8+ Hot Reset, Repair Guides, Check Engine Car Code Reader, Performance Test

Bi-Directional Control, Quickly Locate Problems: Turn your phone into a professional diagnostic tool. You can send commands from your phone to the ECU to test injectors, cooling fans, headlights, A/C clutch, windows, wipers, and more. See which one doesn't respond. Helps you quickly locate the problem and save time. No need to tear things apart, avoid blind disassembly.
Full System Diagnostics, No Fault Hides: Unlike basic diagnostic tools that only cover 4 systems, TopScan can scan all systems. Read and clear trouble codes, view live data streams, and generate a complete vehicle health report – all issues are clear at a glance. Covers 10,000+ vehicle models and is compatible with 99.99% of vehicles.
Flexible Subscription, Choose Advanced Features as Needed: TopScan Lite provides free-for-life access to core diagnostics, including full system scan, code reading, performance tests, and repair information. After purchase, advanced features (bi-directional control, service operations, live data, code clearing, and AI functions) are free-for-the-first-year. After the first year, if you want to use advanced features, you need to subscribe on a monthly, quarterly, or yearly basis. As new models and reset functions are updated, the tool will also be continuously upgraded.
AI Assistant - TopFix: Think of TopFix as your personal AI mechanic. It leverages a repair database and OEM data to deliver clear, step-by-step repair solutions. Features include AI Q&A, one-click translation, and a full repair log, making your diagnostic process simpler and more efficient.
8+ Hot Resets, Keep Your Car in Top Shape: One-tap resets for oil, throttle, EPB, steering angle, DPF, ABS, BMS, and airbag. It enables car owners to easily perform essential maintenance, ensuring the vehicle stays in optimal condition and extends its service life.

This product presentation was made with AAWP plugin.

Last update on 2026-05-13 / Affiliate links / Images from Amazon Product Advertising API

Buffer Email Facebook Flipboard Hacker News LinkedIn Messenger Mix Pinterest Print Reddit SMS Telegram Tumblr X VK WhatsApp Line Xing Threads Bluesky Copy Mastodon Nextdoor