MG Car Repair: Overdrive switch

Question
Barrie, I have a 1978 MGBGT made in UK.The Overdrive switch is on the gearlever.Up to now the switch has been working correctly in 4th gear.Today while driving, it seems that its working in reverse.When I select "in" for overdrive the revs go up,and when I select"out" the revs drop.I had the centre consul/armrest off recently for some work,and I was wondering if I had interfered with some wiring.Any advice much appreciated.Joe.

Answer
Hi Joe
The overdrive switch is not a changeover switch, it is a simple ON-OFF switch.
My guess is that you have put it back together upside down.

Turn the entire gear knob so it appears to be upside down,
and then remove the top cover and fit it the right way up.

Problem solved.