[Healeys] Fw: Gearbox and Overdrive finally separated

[John Harper]

Earl

I fully agree. Trying to reverse a big Healey fitted with an overdrive 
that is stuck in an engaged state and in so doing destroys it is a 
problem often encountered. One of my colleagues has had just that and 
has had to fit a new unit in the last few weeks.

If one is compiling a list of driver's do's and don'ts I suggest that 
every time one tries to reverse an overdrive car that does not respond 
as expected then don't try again except at very low engine revs. You 
might just save the overdrive by doing this.

What happens, in reverse, when the main cone clutch is not engaged is 
that the 'inners' rotate at about 8 times the normal speed depending on 
the O/D ratio. The one way clutch cannot help because this only works in 
the forward direction. The various gears will not stand running so fast 
for long and will 'burst'.

Regards
>
>
>Ken:
>
>Sounds like at some point, the car was reversed with the overdrive still
>engaged - one of the switches likely failed.  We are working on a BN4 box
>with the same mess - totally destroyed planet / sunwheel set, one-way
>clutch, annulus, and gearbox mainshaft.  So far, we've found all the needed
>parts except the mainshaft - the BN4 stuff is getting pretty rare.
>
-- 
John Harper