Mercedes Coupes/Sedans/Wagons 1974-1984 Repair Guide

Manual Transmission



See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: The manual transmission fluid should be level with the bottom of the filler (upper) plug hole

The transmission oil level should be checked at the recommended intervals or sooner. Since there is no dipstick, the level is checked at the filler and drain plugs. In the event that a major loss of oil is found, the problem should be found and corrected immediately.

Check the level when the fluid is hot. You'll need a 14 mm Allen socket to remove the plug. If fluid is needed use Type A Automatic Transmission Fluid (ATF) with Suffix A, or its equivalent.

  1. With the car parked on a level surface, remove the filler plug (upper arrow in illustration) from the side of the transmission housing.
  3. If the lubricant begins to trickle out of the hole, there is enough. Otherwise, carefully insert your finger (watch out for sharp threads) and check to see if the oil is up to the edge of the hole.

The EPA warns that prolonged contact with used engine oil may cause a number of skin disorders, including cancer! You should make every effort to minimize your exposure to used engine oil. Protective gloves should be worn when changing the oil. Wash your hands and any other exposed skin areas as soon as possible after exposure to used engine oil. Soap and water, or waterless hand cleaner should be used.

  1. If not, add oil through the hole until the level is at the edge of the hole. Most gear lubricants come in a plastic squeeze bottle with a nozzle, making additions simple. You can also use a common everyday kitchen baster.
  3. Replace the filler plug, run the engine and check for leaks.


Manual Transmission

The manual transmission oil should be changed at least every 25,000-30,000 miles. To change, proceed as follows:

  1. The oil must be hot before it is drained. If the car is driven until the engine is at normal operating temperature, the oil should be hot enough.
  3. Remove the filler plug to provide a vent.
  5. The drain plug is on the bottom of the transmission. Place a large container underneath the transmission and remove the plug.
  7. Allow the oil to drain completely. Clean off the plug and replace it using a new washer. Tighten it until it is just snug.
  9. Fill the transmission with the proper lubricant. Use a plastic squeeze bottle with a long nozzle; or you can use a squeeze bulb or a kitchen baster to squirt the oil in. Refer to the "Capacities" chart for the proper amount of oil to put in. The oil level should come up to the top of the filler hole.
  11. Replace the filler plug, drive the car for a few minutes, then stop, and check for any leaks.