My 1850 gear-lever Overdrive Switch suddenly went soggy last week and stopped working. I've bought a new one and fitted it and I now have overdrive technology back.
I thought I'd dismantle the old one to see what had failed in it.
I didn't need any tools to dismantle it; it fell apart.
Here are some piccys of the parts. The main switch contact is a brass roller that is moved forward and backwards by a spring loaded plunger from the back of the plastic knob. The switch lever is moved backwards and forwards by sliding it in a metal frame. I found an extra bit of plastic; it was one side of the slide mechanism. The edges of the metal frame are sharp and hadn't been de-burred, so over the years the sharp metal edges had sawn through the plastic and cut it off, giving the soggy feeling and no switch operation.
It was actually stamped with the Lucas logo and has a date code of "1517". Since I don't remember replacing it, that may be Week 17 of 2015. So not that long ago. The replacement I got from Rimmers is rather different, so the previous one may be an E-Bay part.
Its difficult to say if this is a 1-off or a batch problem.