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Hi there Adjusting the modulator is easy - even if you do not have the correct gauges to measure the main pressure and primary throttle pressure. Before I explain how to adjust the vacuum modulator (VM) you first have to understand what it actually does. As you know VM is connected to the manifold balance line on carb engines and to the air distributor on FI engines. Inside the sealed VM housing is a vacuum chamber, diaphragm, tension spring and set screw. The adjustment of the set screw affects the spring tension and thus the amount the diaphragm will move under engine vacuum. On the other side of the diaphragm is an operating pin which transmits the movement of the diaphragm to the primary throttle valve inside the transmission's valve body. Inside the valve body the position of the primary throttle valve determines the primary throttle pressure which directly influences the main pressure which together with the govenor pressure determines the exact gear change point. If all of the above sounds a little too complicated, all you need to know is turning the set screw clockwise increases the primary throttle pressure and will cause the gear change to occur at higher engine speeds. Turning it counter clockwise has the opposite effect. To install the VM is simple. Pull thç;®© hose off and unscrew the VM from the transmission. Some ATF will spill so be prepared for it and the operating pin may come out with the old VM, if it does simply remove the pin from the old VM and place it in the new VM. Replacement is a direct reversal of the removal. Make sure you get no dirt inside the transmission and top up the ATF afterwards. Test drive the car. Do this very gently at first to make sure that the transmission is in fact changing the gears up and down. Then note the speeds at which the gear changes take place. The change from 1st to 2nd under part throttle should take place smoothly between 20 and 25 mph and from 2nd to 3rd under part throttle between 30 and 35mph. This is a rough guide - I don't have the exact speeds on me but I can look it up if you want. Let me know what happens - I hope the above will be of some use. Regards Adriaan Loedolff '69 Squareback Automatic ------------------------------------------------------------------- Search old messages on the Web! Visit http://www.vwtype3.org/list/