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Mercedes Benz 380SL Transmission Slip

Q. I have a 1983 Mercedes Benz 380SL. V-8 and automatic transmission and 107,000 miles. The original transmission was rebuilt due to a 3-4 slip. This occurred when it was cold and as the day went on, the slip went away. But when cold, it was very pronounce. After the rebuild, things were the same. The modulator was changed and adjusted. Now the shifts were too hard and slippage was still there when cold.

Mercedes Benz 380SL Transmission Slip

I went to another shop and they did not want to use the old transmission so we purchased a used transmission with 80,000 miles. This one had slippage in 2-3 range. The supplier sent a third one and still have 2-3 slip, but only when it heats up. When cold, all shifts are fine. When heated up, 2-3 slip is very pronounce, about 500-700 rpm slip.

When I really get on the car and wind out the shifts, all are fine. Under normal driving, all shifts are perfect except 2-3. How can three transmissions continue with problems? What interfaces with the transmission and engine that may be causing this? HELP!!!

Bob

A. There is a Technical Service Bulletin issued for this problem. Your transmission shop can easily check and repair it.

BULLETIN No.: 268
DATE: 1995
TRANSMISSION: 722.3, .4, .5
SUBJECT: Slipping or Soft Shifts
APPLICATION: Mercedes Benz, Porsche

Slipping or Soft Shifts

If a test of modulator pressure shows zero pressure at an idle in drive, try adjusting the modulator. If there is still no pressure, it may be due to excessive clearance between the end of the modulator and the modulator valve assembly.

Mercedes Benz 380SL Transmission Slip

Mercedes Benz 380SL Transmission Slip

To inspect for this condition, remove the modulator. Start the engine and press in on the modulator valve assembly (figure one). If there is now pressure showing on the pressure gauge, make a shim and install it into the modulator valve (figure two).

Mercedes Benz 380SL Transmission Slip

Inspect the assembly to make certain that all clearance has been removed. With the shim installed in the modulator valve, reattach the modulator to the case. Remove the valve body and carefully push the modulator valve assembly against the modulator. Make certain that you use the exact location as shown in figure three. There should be no clearance and zero preload.

Additional Information provided courtesy of AllDATA

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