Marc:
The gearbox numbers are not the numbers usually cited when
referring to the
the box. The number should start with a CC, CD, GR or CF (not to be
confused with the
chassis numbers!). The Moss catalog has some details on gearbox ID. The
number you
want is stamped on the left bell housing, next to where the cross shaft
exits the
bell housing.
As for the ODs, the first 2 digits are the OD ratio, so the
25/xxxx is a 25% overdrive, and the 28/xxxx is a 28% overdrive. The 28%
OD is
not a real TR overdrive, and probably came off a Volvo or perhaps a
Triumph Saloon.
The 25% OD is most likely a real TR6 overdrive, as all J Types on the
TR6 were
25% OD.
To add the OD to your existing tranny will require complete
disassembly of
both boxes, as the main shafts are different lengths and so you will
need to swap the
main shaft as well as transferring over the J-Type OD. This would be a
good time to
do an overhaul, perhaps by using parts from a donor box to rebuild
yours.
There are some problems with this, and since you don't have the
correct numbers
for the box, I can't tell if you will encounter them or not. The main
shafts were
changed at some point, and so may not be swappable without also swapping
the input
shaft. Triumph also changed the pitch on the gears by 5 degrees at some
point, so
the gears will *LOOK* compatible, but cannot be swapped except as a
complete set, which
will require the layshaft and lay gears to also be swapped. You will
need to be very
careful if you attempt to swap components between boxes. One possible
outcome is
that you will not be able to reassemble the box, because the gear
pitches are incompatible.
Another possible outcome is that the box jumps out of gear.
Don't be intimidated, just be aware and check fit CAREFULLY. If
you test fit the
gears, and know ahead of time about the pitch change, you should avoid
any problems.
Cheers,
Vance
------------------------------
Cogito Ergo Zoom
(I think, therefore I go fast)
TR6 Web page: http://home.comcast.net/~v.navarrette/
-----Original Message-----
From: owner-6pack@autox.team.net [mailto:owner-6pack@autox.team.net] On
Behalf Of Marc Nederkoorn
Sent: Wednesday, October 27, 2004 2:08 AM
To: 6pack@autox.team.net
Subject: Gear box identification
List,
Is anyone able to identify the following gearboxnumbers and their
origin?
The numbers are:
MK1053, with Overdrive 25/115868/001412
and
MD11406 with OD number 28/115873/005055.
These are J type OD boxes, I am trying to confirm possible use in my '74
TR6
and/or use components to add the OD to my existing tranny.
Regards, Marc
'74 TR6
The Netherlands
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