All/Alan,
I knew I saw this somewhere before. I searched the archives and presto (now
that I can get search to work) there it was smack in my face. What Alan
described is exactly what happened to my sideshift and the main reason I am now
rebuilding. Here is the operative quote from Alan, the complete version is
found below from the archive 4 years ago.
---------begin quote------------
If this had been in the car, the net effect would have been some
> worn slider/laygear from being
> pressed together, and a 3rd synchro that would have rapidly failed due to
> the car still being in 4th but
> the 3rd synchro engaged. Once the synchro wore enough, the hub and slider
> would could, theoretically
> have been pushed far enough apart that their 3 ball bearings and springs
> would have been able to
> get out and float around the gear box.... Hmmm.... not a pretty sight with
> all those rotating gears.
-------------end short quote--------
Well well, guess what I found in the bottom of my tranny, 2 springs and detent
balls. Also a badly worn 3rd syncro and a missing buffer on the bellhousing.
I suppose I will be making a buffer tonight.
What material works best for folks? Doug Reid mention rubber but does this get
glued in?
Tracy (aint this fun?)--------
-----------full quote bagins--------
Re: BT7 side shifter transmission question (quiz, except I don't have
theanswer!) LONG
--------------------------------------------------------------------------------
Subject: Re: BT7 side shifter transmission question (quiz, except I don't have
theanswer!) LONG
Date: Wed, 27 Sep 2000 16:15:33 -0400
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Alan,
If fitting the bellhousing doesn't sufficiently limit the travel of the
selector rod you can add a buffer pad to the bellhousing, in the bottom of
the hole that the rods protrude into. The factory manual shows this as item
3 on the illustration for the center shift gearbox components. A piece of
rubber 1/8" to 3/16" thick will work, but
be careful not to make it too thick or the slider will not move far enough
forward for the spring-loaded balls to index.
Doug Reid, 18G Motorworks
----- Original Message -----
From: <Alan_Hantke@i2.com>
To: <healeys@autox.team.net>; <owner-healeys@autox.team.net>
Sent: Wednesday, September 27, 2000 1:15 PM
Subject: BT7 side shifter transmission question (quiz, except I don't have
theanswer!) LONG
>
>
>
> I've got a little problem on the transmission I've rebuilt for my BT7.
> Although this is a side shifter,
> the problem is actually germane to all of the later AH transmissions....
>
> The issue resides entirely within the sliding 3rd/4th hub selector.
> Unfortunately the manual(s)
> don't have a good terminology for the TWO components that make up the
> slider so I'll have to
> do this myself. For the sake of clarity, let's call the top member that
> actually engages the splines
> of the 3rd and 4th teeth the 'slider'; this is the guy the shifting fork
> actually moves. It slides back
> and forth on something I'll call the 'hub', which itself has some play on
> the shaft. It is that play that
> allows the synchros to do their job
>
> OK... now that the terminology is out of the way I'll describe the
> problem.... After I finished putting
> the transmission together I tried it out on the bench. R-1-2-3-4 all seem
> to work great, but when
> it 4 and I rotated the shaft around of a bit I heard a sudden THUNK and
the
> shafts suddendly got
> hard to turn. What's this? That can't be, I thought... I'll have to open
> it up again!
>
> This is what I found. The slider was riding right up on the side of the
> laygear, being pushed there
> by it's (the hub/slider) 3 detent ball bearings which were almost free.
> Basically what had happened
> is that the hub slid (back) such that it was being pressed into the 3rd
> gear's synchro (!) which allowed
> the slider to slide so far forward that the ball bearing were able to
press
> the two pieces apart even
> more. If this had been in the car, the net effect would have been some
> worn slider/laygear from being
> pressed together, and a 3rd synchro that would have rapidly failed due to
> the car still being in 4th but
> the 3rd synchro engaged. Once the synchro wore enough, the hub and slider
> would could, theoretically
> have been pushed far enough apart that their 3 ball bearings and springs
> would have been able to
> get out and float around the gear box.... Hmmm.... not a pretty sight with
> all those rotating gears. You
> get the idea!
>
> So, that is the problem. I *think* that the issue is that the distance
> between the 3rd and 4th gears is too
> far apart. This would allow the hub to be able to slide too far towards
> the 3rd (etc etc). The only
> problem is that there isn't any adjustment for this separation that I can
> find (well, we'll get into a theory
> in a bit). Some of the people who are reading this *might* be saying, no,
> the synchro could be too
> thin too. I thought of that, but the synchro is new and in good shape
> (i.e. doesn't look as though it was
> not manufactured correctly). You might also be saying that the bearings
> were not in all the way which
> would result in the input and mainshaft (output shaft) being too far apart
> (3rd and 4th). Unfortunately I checked that
> too. The bearings are seated properly and on their retainer. And yes,
the
> 'mainshaft distance collar' (number
> 45 on the MOSS catalogs, #85 on the A-H parts manual). The split collar
on
> the outside of the transmission,
> under the cup held in by the retaining C-clip (manuals show a nut for some
> reason, but every tranny I've seen
> has the split collar), appears to be in fairly good shape; besides, if
> anything, the split collar would PULL the
> input and mainshaft FURTHER apart!
>
> One could, I suppose, take the position that 'rattling' the first motion
> shaft back and forth isn't a good test and
> that the problem would not exist in the real world; the theory would be
> that the components would be under pressure
> and hence the hub and slider would not go in different directions.
> Unfortunately this seems both risky and not
> quite true. Any transition from the motor pushing to the motor idling
> could be interpreted as a 'rattle' that would
> cause the components to have a momentary 'nothing happening' state.
>
> Lastly, in case you are wondering, yes, the shifter did pop down
> further....... past it's detent. HEY! I think I
> got it! I didn't have the bell housing or the adapter plate on when I
> tried my test! I bet that the shifting fork
> is precluded from that much travel!
>
> WOW! This list is G-R-E-A-T!!!!! I was going to put out the question in
> the hopes that someone could help
> and here I go and figure it out while writing this. Well, I'll post this
> in the hopes that someone else will learn
> from my, ah, stupidity.
>
> --alan
>
>
> BTW, the synchros in a side shifter are bonze
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