Why Does the Mercedes 7G-Tronic (and 9G) Automatic Transmission Jerk?

The video analyzes a Mercedes E63 AMG with 62,137 miles, regularly serviced but experiencing poor shifting. The automatic transmission consists of three parts: the transmission assembly with the clutch packs, the torque converter, and the mechatronics, which electronically and hydraulically manages gear shifts.

The problem arises from wear on the clutch packs: organic abrasion occurs, which ends up in the filter and oil, and metallic abrasion remains in the pan on the magnets. However, the organic abrasion also deposits in the channels and pistons of the mechatronics.

Even performing an oil change (3 quarts + filter) or a drain (5.3 gallons), this deposit does not eliminate: the cleaner only shifts it from one area to another, like in a maze. The result is that the mechatronics pistons, once free, now encounter resistance and lose compression, causing jerks and irregular shifting.

Additionally, the rubber seals between the mechatronics and transmission harden and need replacement. To truly resolve the issue, it must be disassembled, opened, every channel and piston cleaned, and the seals replaced.

The problem is that Mercedes no longer provides the mechatronics as a replacement for many models. Therefore, it is better to intervene with a deep cleaning before it wears irreversibly.