"Clive" wrote in message
...
In message m, Martin
Underwood writes
Do crash gearboxes actually engage the teeth of the gearwheels or do
they engage dog-clutches (ie like a synchromesh box except without the
synchromesh cones)?

Cog meshing went out in the 1920s and since then it has always been
dogs.

So, given that post-1920s gearboxes had permanently-engaged cogs, of which
one at a time was locked onto the shaft by dog clutches, why did it take so
long for manufacturers to add that other little refinement, synchromesh
cones?