The original modulator in a 1981 380sl I'm restoring has a plunger and metal piston that fits directly into the transmission. However, the MB brand modulator I just got to replace the original has a long plastic pin that, according to alldatadiy and the website listed below, is supposed to be placed between the plunger and the piston presumably to account for temperature changes.
MERCEDES 722.3 MODELS 107 123 126 COMPENSATING PIN FOR THE MODULATOR VALVE IN EARLY 1981 PRODUCTION A PLASTIC COMPENSATING PIN WAS INSTALLED IN THE VACUUM MODULATOR AND THE CONTROL PRESSURE SLIDE VALVE (MODULATOR VALVE). THE COMPENSATING PIN ALLOWS FOR THE EXPANSION OF THE MODULATOR VALVE INORDER TO PREVENT VARIATION OF THE MODULATING PRESSURE DUE TO THE VARYING TEMPERATURE OF THE TRANSMISSION. THIS IS DESIGNED TO IMPROVE THE SHIFT CHARACTERISTICS OF THE TRANSMISSION DURING START-UP AND BEFORE THE
http://autorepair.about.com/library/faqs/bl160h.htm
http://www.alldatadiy.com/alldata/AFI~V13956416~C10083~R0~OD~N/0/41745938/56620861/56620871/56620872/34853741/34860071/34860072/56227463/14411668
However, the pin-piston combination is far too long to fit into the transmission housing, which was obviously designed for the old-style modulator. So I was wondering if anyone here can tell me how this newer modulator can be installed in the way the above sites show.
Thanks a lot for any info anyone can give me on this.