[Fot] TR4-6 trans into TR3

[Randall]

> I have been carting around a TR3B transmission for three 
> decades assuming some day I would put it in my TR3 for the 
> synchro. It does infact have the dipstick hole but I remember 
> driving the car (TR3B) and liking the synchro before I parted 
> it out when they were worthless ($500). Do you think there 
> were cross over years?

I don't believe so.  The dipstick was deleted several years before the 4
synchro box was created (at the same time the main casting was changed to
accommodate the later starter, at TS50000); and if I recall correctly, later
3As didn't even have the hole in the tunnel to access the dipstick.  But as
I mentioned, it's easy to adapt the dipstick top cover to the later box;
possibly someone knew that even 30 years ago ?

> Any other tips from the outside that 
> its a synchro,

The 4-synchro box has a large cylindrical bulge on the LH side, right behind
the fill plug.

> will it take the overdrive unit from my 
> older non-synchro transmission if I ever get motivated to 
> exchange it?

You'll need the OD mainshaft to match the gearset in the box (meaning a
different shaft between 3-synchro and 4-synchro).  The adapter plate also
changed slightly, but I believe the early plate can be modified to fit the
later box by removing some metal with a die grinder (to clear the end of the
countershaft).  But since the early plates were somewhat weak anyway and
prone to leak; it might be better to just buy one of John Esposito's uprated
plates.

Randall