Gonna need younr expertise on this thing. To my visual inspection everything seems normal. Into and Ou of reverse shows the bar in the extension housing move to allow the switch to move. Up and down. Although I think something is missing because old switch allows the reverse lights to stay on in any gear. As well as the new switch, same problem. Testing the switch shows the switch is normal, both new and old switch. Chiton says nothing but unscrew and thread in new switch. And possible remove gear oil to remove switch depending on switch location.
Pics preferred because I don't know how the extension housing is supposed to look in the reverse switch location (switch removed pointing inside extension housing).