Maintaining the proper fluid level in your automatic transmission is crucial for smooth shifting, longevity, and overall vehicle performance. This guide provides step-by-step instructions for checking and maintaining transmission fluid levels in your Mercedes-Benz R107.
Why Checking Transmission Fluid is Important
Ensures smooth gear shifts and prevents transmission slippage. Prevents overheating by providing proper lubrication. Extends transmission life by reducing wear and tear. Avoids costly repairs caused by low or contaminated fluid.
When and How to Check Transmission Fluid
Check the fluid level regularly and always before long trips.
Step 1: Prepare the Vehicle
Park the vehicle on level ground. Engage the parking brake. Move the selector lever to position “P” (Park). Start the engine and let it idle for 1-2 minutes to warm up the transmission.
Step 2: Locate and Measure the Fluid Level
Locate the dipstick and ensure it is fully inserted with the locking lever released (1).
Use a clean, lint-free cloth to wipe the dipstick before taking a reading.
Insert the dipstick completely, then remove it again to check the fluid level.
Extreme cleanliness is required—even the smallest impurity can cause transmission issues.
Understanding Fluid Level Readings
The fluid level varies with temperature: At normal operating temperature (80°C / 176°F):
- The level should be between the maximum and minimum marks on the dipstick.
At shop temperature (20-30°C / 68-86°F):
- The fluid level may be 10mm (0.4 inches) below the minimum mark.
- This is normal after a fluid change when the transmission has cooled.
Important:
- DO NOT overfill the transmission—excess fluid must be drained or siphoned if it exceeds the max mark at operating temperature.
- Always reinstall the dipstick securely by pushing it all the way in and swinging the locking lever down (2).
Adding or Changing Transmission Fluid
If fluid needs to be added: Use only the recommended ATF specified for your Mercedes-Benz R107. Pour the fluid slowly through a fine-mesh filter into the dipstick opening to prevent contamination. Recheck the level using the dipstick after adding fluid.
Warning:
- Never mix different types of transmission fluid, as this can affect performance.
- If the fluid appears dark, burnt or has debris, a full transmission fluid change is recommended.
Key Takeaways
Regularly check the fluid level to maintain transmission performance. Measure only at the correct temperature for accurate readings. Use a fine-mesh filter when adding fluid to avoid contamination. Never exceed the maximum fluid level—overfilling can damage internal components. Ensure the dipstick is fully inserted and locked after checking or filling.
By following these steps, you can prolong the life of your automatic transmission and keep your Mercedes-Benz R107 running smoothly for years to come. 
