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Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 54039
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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Mercedes-Benz 300D How do you adjust transmission pressure

Customer Question

How do you adjust transmission pressure on a 1981 Mercedes 300SD. Considering all seals and valve body gaskets are intact. I want to know for a fact where my gauge connects, then how to manipulate the vacuum modulator adjustment if in fact I needed an adjustment
Submitted: 6 years ago.
Category: Mercedes
Expert:  Marty replied 6 years ago.

eurotec :


eurotec :

I will attach some information showing the test points for the transmission pressures.

eurotec :

Just realized that you probably have a 722.1 transmission.

eurotec :

The info I posted is for a 722.3 transmission.

Customer: Thanks but please send a procedure with specs to compare my readings to
eurotec :

The procedure is basically the same for a 722.1. The modulator pressure is 3.0 bar. To be honest with you I do not use a pressure gauge. I make sure that the valve is getting vacuum and then soften or firm the shifts by adjusting the modulator valve by feel.

eurotec :

Turn the adjustment in to firm up the shifts and turn it out to soften the shifts.

Customer: Thanks bud, on another identical car. I had a symptom that felt like a misadjusted modulated. The car shifted at excessively high rpms . I would let off the gas then hit the pedal again to make each shift. Makes me crazy, I know the significance of that adjustment just didn't know how to perform it.
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