Rick Long, I had the opposite problem. I don't believe any of these extender are safe from eventually going bad & causing a slow leak.
TXredfish. You may try removing the extender & installing the valve core with the hose staight. There is an adjustment on the extender that allows the long rod of the core to press against the valve core in the wheel (not the extender) thus making it possible to apply air pressure to the extender then airing up the tire. If you adjust it to tight it will allow both cores to be depressed & air to escape from the tire. You should spray a soapy mix on the stem & extenders with the valve cap off, if there is a leak it will bubble. I use windex or similiar. It is possible to remove the extenders with the wheels on. It can be a challenge & may require a pair of long needle nose pliers.
Dan Sees, Full Timing in the MH & Part timing in a S&B In Hampstead, NC
2013 Winnebago Journey 42e, 2014 Featherlite Car Hauler 3110 17.5', 2008 Mazda MX5,
2008 Toyota FJ Cruiser