[Healeys] Gearbox jumping out of 4th gear coasting downhill or decelerating

[A H List]

Hi Bob,

You are right, the detent won't hold the gear in if there are other
issues such as worn or missing parts but they do sometimes drop out of
gear on overrun or light loading just because the gear lever boot is a
bit stiff. Later designs solved the issue by 'dovetailing' the shift
collars which tends to pull the gear further into engagement under
power and decel. This pic shows the very subtle machined dovetail
where the teeth sit when engaged, maybe that is what DW has done.
https://images.cmsnl.com/img/products/sleevesynchronizer_big23622611000-01_5351.jpg

Andy.

On 11/8/17, Bob Spidell <bspidell at comcast.net> wrote:
> Thanks, Andy.
>
> WRT the indents in the shift rails, I'm of the opinion that the shift
> rails and forks should not be depended on to hold the gearbox in gear.
> When my BJ8 started popping out of 4th, I tried holding it in gear with
> the shift lever; the force required to do so was substantial, and it
> occurred to me that fighting a gearbox that wanted to go out of gear
> could result in a broken shift fork (which would have created a real
> inconvenience when 100 miles from any town and well out of cell phone
> range).  I plan on ordering DWR's improved 3/4 hub, which they claim
> helps alleviate the jumping out of gear problem, along with new
> synchros, shifting forks and layshaft.
>
> Curiously, when I pulled my input and main shafts apart, I don't recall
> the caged bearing set falling out.  I had noticed that the input shaft
> wobbled a bit more than I thought it should; if we neglected to put
> those bearings in at the last rebuild it's a wonder the box stayed in
> gear at all!  Also, the tip of my input shaft had more wear than
> expected, which could well have been from it wobbling a bit more due to
> the missing bearings.
>
> Bob
>