Just wanted to say thanx to several listers who provided answers to my
question about the diff. between O/D mainshafts and non-O/D mainshafts.
Especially Ed Woods who pointed out that O/D mainshafts are not threaded
at the tail end (where non-O/D unit would be to connect to the
driveshaft) and that there is no scroll gear to drive the speedo on the
O/D model.
All I can say is "duh"!
So this evening I did another test fit after confirming the shaft in my
gearbox was in fact O/D compatible (my apologies to the un-named
vendor). I didn't want to force anything and do any damage! Turns out
loosening the speedo take-off and turning the drive shaft got everything
to line up & slip into place. So now all I gotta do is clean up and
rebuild the O/D itself. Glad I did the test, because the 4 shorter studs
that hold the unit to the gearbox adaptor are way too short & will need
to be replaced.
I also learned that there were at least two distinct A-type O/D units
used: early (TR3 & 4) and late (4A & early 6). The one I picked up is an
early model, which means there are two springs in the accumulator pump:
one monstrous outer one, the other smaller, inside. The accumulator
piston itself is 1-3/4" in diameter. The later model has a 1-1/8"
piston. The later style has a single spring and a sleeve or tube.
The earlier O/D's also had an exposed operating lever and solenoid. On
later ones this was enclosed in a box.
There are also minor differences in the attachement of the strainer at
the bottom oil pump.
This is all kinda academic, except I notice in the factory manual that
the downshift points are musch higher on the later O/D. With the earlier
you're warned against over-revving if you are in O/D at more than 3500
rpm and disengage O/D into 3rd or 2nd. The later model can handle up to
4500 rpm according to the manual.
Alan Myers
San Jose, Calif.
'62 TR4 CT17602L (& .6 "O")
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MZ
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