Hello All,
1971 C60 - 5 speed trans - 2 speed rear.

Hope you can help with this.
Must be a replacement tranny as the glove box tag says SP3152F but the hole in the floorboard is ROUGHLY enlarged 3-4" towards the rear to accept the shifter.
The switch is on the upper left.
It spins easily.
The retaining bolt is tight.
When it's in reverse I have no continuity on the switch poles.

Thoughts and / or part numbers??

TIA.