W114, Transmission

We just bought a 1974 280C from the second owner.
Jack, reluctantly sold his "baby", because, now entering his late 70's, hip replacements have made entering and sitting painful for him. He broke the map pocket on the driver's side swinging his legs into the seat.
The speedometer's 76000 miles appear to be reasonably accurate... tires mounted in 2001 were recorded @ 71000mi (and there aren't that many miles to drive on a small island like this one), etc. He has kept the coupe immaculate.
Is the dashboard instrumentation a weaklink on the W114?
The VDO quartz clock is non-functioning. Jack velcro-attached a tiny digital clock to keep time.