[TR] TR6 overdrive transmission in a TR3A?

[Randall]

> There's a TR6 Overdrive on ebay.  I'm told it's possible to put a
> TR6 transmission in a TR3.  Has anyone tried this, and have 
> any input on the difficulty of the conversion?

In a nutshell, as long as it's an A-type OD, then it's not hard at all, but
there are some minor adjustments to be made.  Most important will be
elongating the holes in the rear crossmember, to accommodate the additional
3/8" overall length of the TR6 box.  With such an early TR3, you'll also
need to modify the gearbox tunnel to some extent, to clear the larger
starter bulge.

My suggestion would be to rebuild your existing top (shift) cover with the
TR6 forks & shafts.  That will let you keep the TR3 shift lever and the
dipstick/fill hole.  Your old cover should already be drilled & tapped for
the OD lockout switches.

I would also suggest swapping over the front cover (where the TOB rides)
from your TR3 box.  Not essential, but a good idea IMO.

You'll need the longer speedo cable, but I wouldn't use the TR6 angle
adapter.

Don't recall for sure offhand, but you may need longer studs for the back of
the engine block, to fit through the thicker flange.

> If that's the case, I suppose it would be desirable to keep 
> the current transmission, even if the body and the engine and 
> everything else is probably wrong...  :)

It's your car, it should please you.  My point of view is that an OD is well
worth having the "wrong" number way down under the car, but that's just me.
I wound up with a late TR6 gearbox, early TR3 top cover and TR4 A-type OD
(with the big accumulator) which is about the best of all the parts, IMO.

PS, the J-type is a more difficult conversion, requiring more modifications
to the car and some fabrication.  Not as desirable, IMO.

Randall