Mercedes 722.3x Turbo Diesel Transmission Vacuum Modulator UPGRADE (Green) with Installation ONLY Instructions

This is the new upgrade transmission vacuum modulator valve along with the factory genuine OE upgraded plastic thrust pin. When replacing the modulator you should also replace the pin. In the mid 1990s Mercedes modified this unit for better shifting performance. The new version has a better built and more efficient vacuum containment chamber and the trust pin material was modified and the pin slightly lengthened to reduce variations in pin length with extreme temperature changes. Modifications were made to improve cold start shifts from 1st to 2nd gear and reduce flaring when shifting between 3rd and 4th gear. There are other things that can cause problems with poor shifting, so there is no guarantee this new part will fix them. But due to the cost and ease of installation this is a good place to start. 

IMPORTANT: There is no easy way to visually determine if your transmission has the upgraded modulator. If it has been rebuilt within the past 15 years then you should be ok. But I have found modulators are often only good for 15 to 18 years. Just image how many times that diaphragm is moving in and out while you are driving. My recommendation is that you replace it first when troubleshooting transmission shifting problems. Proper adjustment is required and you can not do it by guess or by feel. Once you know the modulator and pressure are correct you can move on to vacuum system troubleshooting and fine tuning. 

This kit comes with the following:

• New Modulator Valve
• New black rubber key cap
• New plastic thrust pin
• Installation instructions ONLY

NOTE: Adjustment and fine tuning vacuum instructions ARE NOT included.

The modulator is located on front left side of transmission body, for 123 and 126 Chassis Turbo diesels from 1981 to 1984 ONLY. Failure of this valve diaphragm causes hard or abrupt shifting. Please inspect your valve and confirm it is GREEN before ordering this replacement. Modulator pressure should be checked any time you are debugging shift problems. It must be checked and adjusted when installing a new modulator. When the modulator pressure is too high or too low your transmission will suffer. A new kit that will allow you to check and set your own transmission modulation pressure will be launched by mid February 2010.