I purchased some rather spendy extenders when I had new tires put on a couple years ago at Dickman's (Les Schwab in Junction City Oregon). I don't remember the product name, but it did include the grommet and angled stems on the outer tires and longer ones coming through from the inner tires. I also put the same TST flow through monitoring system on mine. From time to time I've had these monitors stop working, and have had to remove them, and reset them (is the best way I have found) by simply removing or if the battery is low, replacing the battery. I also didn't install any of the rubber O-rings that were sent with the kit, but found eventually that my driver's side front monitor stopped working, so I took it off, noted some signs of water ingress, put the O-ring in and it worked again so I've since removed all the monitors opened them up and put the O-ring in. I guess you should too unless yours already have O-rings in them. Mine did not.
Another thing I have noticed is that the flow through valves are not as easy to get air into as simply removing the monitors and filling directly to the valve stems. Also be careful that you screw the in tightly enough but not too tightly as either condition can cause them not to work correctly and even leak.
Mike
