The early automatic transmissions in the Mercedes Benz 280 Sl Automatic, often recognized by their 16-bolt oil pans, are known for delivering a firm shift, a characteristic different from today’s smoother transmissions. When properly maintained, these transmissions provide a comfortable driving experience, with shifts that are noticeable but not jarring during normal acceleration and deceleration. Applying more pressure to the accelerator pedal will result in later and firmer shifts, while engaging the “kick down” feature or downshifting to lower gears will produce more abrupt transitions. For precise details on shift points at various speeds and settings, refer to section 27 of the Mercedes-Benz service manual, specifically the specifications for the KA4 025 transmission, as other transmission types are also documented within the manual.
A crucial first step in ensuring proper transmission operation is verifying the functionality of the three-position solenoid located on top of the transmission. This solenoid, along with its associated linkages and pivots, can become stiff or আটকে due to corrosion or lack of use. Inspection of these components can be performed through the access opening in the transmission tunnel. Detailed information regarding the solenoid, venture switch, and linkages can be found on pages 27-23/3 through 27-23/5 of the service manual.
Adjusting the modulator pressure should only be considered after confirming that all linkages, switches, and the solenoid are operating correctly. This adjustment is a more complex procedure, requiring a specialized fitting to access the test port and a basic pressure gauge. Modulator settings are listed on page 27-0/3 of later service manual editions, while page 27-23/14 describes the process of “Measuring of Kickdown Modulating Pressure,” and page 27-25/5 provides further details on modulator pressure measurement. If access to the service manual is unavailable, consult the Tech Manual on this website or seek further assistance.
For those unfamiliar with the correct shift feel of a properly functioning transmission in a Mercedes Benz 280 SL automatic, driving a model known to be shifting correctly can be highly beneficial. This firsthand experience provides a valuable reference point for understanding the intended performance.
