Thanks, Henry, and also Fred Thomas for additional info. It does sound
complicated and expensive, but worth the trouble!
Sumner
----------
> From: Henry Frye <thefryes@iconn.net>
> To: Sumner Weisman <sweisman@gis.net>
> Subject: O/D - Was Manchester Show
> Date: Wednesday, September 16, 1998 9:12 AM
>
> Hi Sumner,
>
> From the guy who just did it...
>
> All the public posts have been correct. It is complicated, and expensive.
>
> I scrounged up all the parts, and gave them to a local TR gearbox guru. I
> found a 'needed to be rebuilt TR3 non-four speed syncro O/D gearbox'
cheap.
> Probably should have waited for a O/D better box, I know it ended up
> costing me in the long run. I also had a decent TR4 gearbox in the shop,
so
> that was the box that got rebuilt, and the O/D was grafted on. The tough
> part to source in this scenario is the mainshaft. The O/D requires a
> different mainshaft in the gearbox. You also need a different adapter
> plate. That goes between the back of the gearbox and the front of the O/D
> unit. The one that came on the back of the TR3 non-four speed syncro box
is
> different.
>
> So, having delivered all the parts to the gearbox guru, the guy stripped
> both boxes. Upon inspection of the TR4 gearbox, other than the "normal"
> $200 kit of rebuild components, I needed a new input shaft (which is 4th
> gear) and the gear that meshes with the reverse idler. Luckily, he sold
me
> good used parts he had in his stock for CONSIDERABLE less than retail.
The
> parts we needed for the O/D unit was another story.
>
> The O/D unit was in need of lots of stuff. What happens is the gearbox
and
> the O/D unit share the same oil. The O/D runs on oil pressure derived
from
> an oil pump that runs off the mainshaft. There is a strainer that will
keep
> the big chunks of stuff out of the high pressure circuit, but the
strainer
> lets all the fine particles through. Not good.
>
> As a gearbox wears, the thrust washers and roller bearings start
> desegregating, and little chunks of metal flake off into the oil. The
small
> chunks get past the strainer, go through the oil pump into the
accumulator.
> The accumulator is a big piston that holds the bulk of the pressure that
> the O/D needs to engage. When the O/D switch is thrown, hydraulic
passages
> are opened to bleed off pressure from the accumulator and move the
> operating pistons.
>
> The movement of the accumulator piston and the operating pistons with the
> small flakes of metal in the oil is a recipe for disaster. When the bores
> the pistons ride in get scratched up, you start losing pressure. Then the
> O/D will stop engaging positively. Then, things start getting real
> expensive...
>
> So, lots of O/D parts were needed. Some are still available from the Big
> Three, some not. We got most of the stuff we needed from Quantum
Mechanics,
> (John Espisito, in southern CT somewhere...) John is another gearbox
guru,
> and he builds lots of O/D boxes. He needs so many parts that he orders
them
> from England in bulk.
>
> Bottom line: I paid for the TR3 O/D gearbox, all the rebuild parts, and
of
> course, labor for my guru. I had the TR4 gearbox in my shop, so whatever
> the cost of that was, it is mot factored into my calculations. Total cost
> was $1150, not including installation. I pulled my TR3B gearbox, and
> installed the O/D gearbox myself.
>
> Adding to the cost of this was a clutch kit, as I always replace these
> components when I am in there. $200
>
> Then, the wiring harness and the proper dash switch and relay was another
> $100.
>
> Now, here is the dilemma. What I paid was about the same as John Espisito
> gets for one of his rebuilds. I would have had none of the running
around,
> none of the heart wrenching phone calls saying now we need this part and
> that part, etc.
>
> But, I got a trustworthy local mechanic who stands behind his work, and
> will be there when I have a problem. He knows the gearbox, and has been
> very helpful.
>
> So, that said, would I do it again? Sure, in a heartbeat. It is that
nice.
> But, it was very costly, and will no doubt add major headaches in the
> future. If the car is used regularly, it should be fine. I am concerned
> with the winter storage scenario, as the O/D's have been known to hang
up.
> (Remain engaged) If they remain engaged, and you use reverse for any
> appreciable distance (From what I have heard, a few car lengths) you will
> ruin a part in the O/D that is listed in the books at over $400, the
> annulus. Great design, huh???
>
> Why didn't Triumph just design a 5 speed gearbox??? 'Cause they are
British!
>
> As if this is not enough info, I would be happy to chat with you about
this
> subject.
>
> Later.
>
> At 09:56 PM 9/15/98 -0400, you wrote:
> >
> >Listers,
> >
> >Now that I think about it, what is involved in adding an overdrive to a
> >non-overdrive TR-3B transmission? I never actually considered it
before,
> >but am getting braver these days. Keep in mind that I am "transmission
> >technology impaired" when you reply.
> >
> >Thanks!
> >
> >Sumner Weisman
> >
> >
> - - - - - - - - - - - - - - - - - - - - - - - - - _
> Henry Frye - thefryes@iconn.net - Connecticut, USA
> TR3B TCF1927 L Driver
> TR250 CD690 L Soon to be Driver
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>
> Homepage http://members.iconn.net/thefryes/
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