John:
I am fairly confident the Moss Catalog is wrong on that point
(the usual caveats apply to this information). My research showed that
the gearboxes were, in order; CD, CF (Beginning with the CF chassis
numbers) and then, perversely, CC. So the gearbox prefixes do NOT go in
chronological/alphabetic order. There were several changes along the
way, the most notable being that the mainshaft used the "pressed in"
first motion shaft bearing in the CD series, and the free caged bearing
beginning with the CF boxes. For the CC (at least, perhaps earlier)
boxes, the angle of the helical gear teeth on the gears was changed by 5
degrees, which means gears cannot be interchanged with the earlier boxes
unless they are replaced as matched pairs. You may also need to replace
the countershaft gear depending on whether you replace first gear. Whew!
It's starting to get ugly....
Moss also says that the gearbox number is always found on the
left side of the box, next to the cross shaft bushing. But the CC series
boxes have it on the right side of the gearbox bell housing, on top of
the starter motor "bulge".
I will attach the usual disclaimer to this information, since I
am faaaaar from an expert on these things. All I can say for certain is
that my 74-1/2 had a CC series gearbox with the free floating first
motion shaft bearing. I know because I replaced it during my
rebuild/J-Type conversion.
Only those boxes with the free floating bearing can be used for
J-type OD conversions. The J-Type mainshaft uses the free floating
bearing as well, and the free floating bearing is not compatible with
earlier first motion shafts. So to convert a CD series box to J-type
will necessitate replacing the first motion shaft, 4th gear cluster,
first motion bearing and mainshaft at a minimum, perhaps more (not sure,
never done it before).
I *THINK* the TRF catalog has the most detailed information on
this. There were many changes phased in over the life of the boxes, and
of course boxes were swapped between cars for the sake of maintenance,
etc. So always proceed with caution and do not depend on the commission
number to buy tranny parts.
I can forgive moss for their apparent error on the gearbox
serial numbers. It is very confusing since there were so many changes.
Cheers,
Vance
-----Original Message-----
From: owner-6pack@autox.team.net [mailto:owner-6pack@autox.team.net] On
Behalf Of Lumia, John
Sent: August 22, 2005 8:22 AM
To: 6pack-digest@autox.team.net
Subject: transmission serial numbers
I was looking at the Moss catalog and it says that gearbox from 75-on
started with CF. The gearbox in my 76 is a CC number, so I am curious
to know if it is original. Does anyone out there have a gearbox
beginning with CF? Thanks.
John Lumia
76 TR6
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