[ram_g]

I agree with Marty, it seems improbable that your transmission has developed a fault that does not appear common, whereas the switch being defective is quite common.

One way of harmonizing both views is to reflect on the fact that we don't really know what the functional specification was in the first place, for how much deflection was needed to activate the switch. Perhaps GM and/or ZF specified a very small deflection to activate the switch, whereas over time the switches become less and less sensitive needing more deflection to activate. So when you're bench testing your switch, you're pressing down enough to activate it, while a new switch would be much more sensitive and capable of switching on the reverse lights with just a tiny input from the transmission. This is all just conjecture, of course, but as I said maybe a way to see how both "facts" would align.