[TR] TR3A A-Type Overdrive Oil Change

[Randall]

> I didn't realise that feature was 
> deleted on later cars.  

Yup, removed at TS50000, same time the transmission tunnel was slightly
reworked to clear the bigger starter bulge, required for the later starter
and flywheel.  The dipstick was replaced by a fill plug on the side of the
gearbox, which doubled as a level indicator.

What's interesting is when someone accidentally mates a later top cover
(without the dipstick) with an early gearbox (without the plug).  Result is
no way to fill it or check the level.

Randall