> Can a TR6 A-Type overdrive transmission be used in a TR3?
Yup. Have to make some minor mods, like new holes in the rear crossmember
and some massaging of the transmission tunnel, but it works slick. If you
keep the TR3 clutch, you'll also need to swap the transmission front cover
with your old one, for proper support of the TOB. Some of the bolts & the 3
studs in the back of the engine block need to change, too as I recall. (The
TR6 gearbox has a thicker front flange.)
> I heard that the input shaft is different.
It is, the TR6 version is somewhat shorter, meaning it doesn't penetrate as
far into the pilot shaft bushing in the end of the crankshaft. But in
practice, it seems to work OK. Lots of people (including me) have done it
with no problems.
> If this would make it not work, is there any
> conversion that could be done using parts from a TR3 4-speed transmission?
An early TR6 A-type OD can be installed to a TR3 transmission, all you need
is the correct mainshaft (which is different). If memory serves, the TR6
adapter plate will work (although maybe it has to be modified slightly ?).
ORS in England claim to be able to modify your old non-OD shaft to take an
OD.
http://www.overdrive-repairs.co.uk/
But with shipping both ways, it's probably cheaper to source the shaft you
need in the US. Try John Esposito, he might have some.
http://www.quantumechanics.com/
All the other tasks of installing an OD still apply of course, like drilling
& tapping the top cover for the isolation switches, plus a complete teardown
of the gearbox to change the mainshaft. Might as well do the countershaft
bearings & thrust washers while you're there, since they are a weak spot.
And the synchro rings are probably worn too.
Anyone know if the synchro rings being sold by the "big 3" are any good yet
?
Randall
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