Charlie,
First, I have absolutely no first hand knowledge of the J-type, but......
since no one else has stepped up to your request yet, I'll share what I do
know.
I recently installed an early A-Type in my formerly non-OD TR3A. What I
did, is different from what you are proposing, but some of what I learned
(mostly from the regular Triumph list) applies. During the tranny swap, I
also converted my car to the later (TR4A-6) diaphragm clutch, which I would
recommend you leave in place as it is a better system than the TR3 clutch
system, especially if you already have the parts, including the flywheel,
which has a different drilling for the diaphragm clutch instead of the
earlier coil spring type. BTW - I am very happy with the LuK clutch
components I installed as opposed the to Borg and Beck or Laycock.
To install a syncromesh tranny in a TR3, you may need to elongate the holes
the rear mount attaches to. I am certain that if you had a non-syncro TR3
tranny in your TR3, the syncromesh unit (TR4 tranny, probably TR4A-6 too) is
about a half inch longer and the mount will have to be modified. Do it
right and slot the tranny mount holes with a rat tail file (thanks Ken
Gillanders), don't just force fit it. The syncro tranny is longer because
they had to make room for the syncro. I suspect it is the same or similar
with the TR6 J-type tranny. Again, I have not dealt with the J-type, so I am
not certain.
The TR3 nose piece on the tranny, on which the Throw Out bearing sleeve
rides, is slightly longer than the one on the later TR4A-6 and will foul a
diaphragm clutch if not used. You should already have the right one on the
TR6 gearbox. Don't swap in the one from your TR3 gearbox, without
shortening it. The Moss catalog has the dimensions for both.
The OD oil recommendations I have heard range from gear lube to Valvoline
racing 20W-50 motor oil and Redline synthetic MTL. The TR manuals say Gear
lube, the AH manuals say motor oil. Almost identical OD unit on both. but
the TR's run higher pressure. Go figure. I am using the Valvoline, but may
convert to Redline MTL this winter. I'm still undecided.
For further information, check the Triumph list archives (FOT archives are
different) at http://www.listquest.com/lq/search.html?ln=triumphs. I know
these issues have been discussed at some time on the Triumph list.
Regards,
Jack Brooks
1960 TR3A
1974 Norton 850 Commando
Hillsdale, NJ
> FOT,
>
> My Dad has located a TR6 J Type overdrive transmission and would like to
> install it in his non-overdrive, street driven 1958 TR3A.
>
> Has anyone done this conversion? What, if any, problems lie ahead for
> us? Can we use a TR3 clutch & release bearing? Do we need to fabricate a
> custom rear mount? Will the TR3 drive shaft be the correct length? What
> type of oil should be used in a J type overdrive?
>
> Any advice is appreciated.
>
> Thanks,
> Charlie
>
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