Michael,
Regarding your TR4A O/D:
It should fit right in with the usual modifications in addition to the
mainshaft (not easy to find, I think Triumphs Only may have some used
ones - www.triumphsonly.com - all the usual disclaimers ;-)
The usual modifications: You will also need the adaptor plate, w/the two
gaskets, that goes on the back of the gearbox to mate up with the O/D.
Also, the cam that rides on the mainshaft to operate the O/D pump. Plus
the solenoid & two "inhibitor" switches to mount in the top cover of
your gearbox. You'll need a wiring harness (two pieces), a relay and a
dash switch. Try to get as many of these pieces as you can with the O/D,
as some are pretty expensive to buy from the big vendors. You may also
want to modify your gearbox cover with access holes for the solenoid
adjustment and the operating valve plug.
Recently exchanged a lot of e-mails with Brad Kahler about the various
A-type O/D models, trying to decide just how many their were.
Just found what looks like a pretty complete answer in Moss' latest
catalog. You are correct: 22/61753/serial # is the TR4A IRS model. It
appears to share the least internal parts with the 3 previous models. It
will also probably have the angle drive installed for the speedo cable,
so you can use the later, shorter cable.
All four O/D's are interchangeable.
The earliest is 22/61275/serial #, used on TR2's up through TS5979. This
is the "weakest" model, as it doesn't deal as well with the torque of
2nd & 3rd gears.
22/61374/serial # was used on TR2 TS5980 up thru TR4's in October, 1964.
(This is the model I just bought, interestingly with 22/1374/serial #,
note the 6 is missing! Wonder what it came out of!). Reading my factory
manual, it appears this model too is a bit limited, with a warning not
to downshift from more than 3500 rpm while it's engaged.
The next model is 22/61712/serial # fitted to TR4's from October '64
through the TR4A line, solid axle models only. This and the following
model are rated up to 4500 rpm downshifts.
The final model (yours) was 22/61753/serial # was supposedly installed
on TR4 IRS models (and maybe 250's, 5's & pre J-type TR6's?). Hmmm, I
wonder why a separate model was spec'ed for the IRS? Also, I see in your
correspondence below that the unit you found appears to be out of a
solid axle car (CT prefix, not CTC).
Alan Myers
San Jose, Calif.
'62 TR4 CT17602L
Michael Marr wrote:
>
> Am I right in thinking that the overdrive gearbox mentioned in the
> attachment will fit my TR3A with little modification, apart from a shorter
> drive shaft?
>
> -----Original Message-----
> From: Ed Reeve <ereeve@erols.com>
> To: Michael Marr <mmarr@idcnet.com>
> Date: Saturday, April 24, 1999 10:11 PM
> Subject: Re: O/D Gearbox
>
> >Sorry ive been out of town for a few days. It is to a TR4a I believe.
> >Stanpart .Laycock de Normanville Overdrive Unit. Serial no.
> >22/61753/004459 Ct 73615
> >900. Tel 703-444-1436 After 2pm Sunday. Regards ed
> >Michael Marr wrote:
> >
> >> I never saw your original post. Is the Gearbox for a TR3A or TR4A? How
> >> much do you want for it? How are the synchros?
--
MZ
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