Greetings everyone! I've seen a number of posts about the modifications
necessary for installing a TR4 OD gearbox into a TR3A, so maybe this'll be a
revelation to some. I have a '59 TR3A with what I thought was a TR4,
4-syncro gearbox. I'm in the middle of installing an OD box out of a
composite TR4/4A donor car. I thought I'd have no problem with the rear
gearbox mount since I already had the 4-syncro...just assumed the bracket
would have already been modified.
Well, not exactly...the two holes in the gearbox mount had been modified all
right...instead of being elongated, they had been cut away so that the hole
is not a hole, but a notch toward the front of the mounting bracket. Totally
open on the front edge. OK, I can deal with that. It held the old box in,
surely it can hold the new one.
When I (finally) got the *&^$&^%# splines to line up and the *&^$&^%#
gearbox bolted to the engine, I installed the crossmember and gearbox mount
only to find that the back end of the OD unit hits the front end of the
mount and won't let the gearbox drop all the way down.
Well, as I said, the gearbox came out of a mix-n-match car and the
crossmember from that car is about 1/4" wider (front to back) than the one
that was in my '3. The holes for the bolts that hold the crossmember to the
frame are nearer the front edge of this bracket, and the holes for the
actual gearbox mount are off-center (front to back), nearer the back ...
makes a perfect match! The crossmember fits my car, and the gearbox holes
line up EXACTLY with the holes in the bracket. No drilling, no cutting, no
rat-tail filing...just bolt it in! Finally something went right with this
project!!
According to the Moss catalog, the TR3 and 4 brackets are the same part
number, but the 4A is different. I would think that the 4A one is the larger
of the two and that it is the one that I now have on my car. Not sure
though, because the picture of the 4A crossmember in the catalog does NOT
look like either of mine. Both of mine look like the one shown for the TR4
except the rear lip extends farther back by 1/4" on the one I used.
Obviously, I don't know for sure what's in my car, but I do know it's an
official TR part. So...if you intend to install a 4-syncro w/ OD in a TR3A,
see if you can get your hands on the larger bracket, whatever it's from, it
works!
Life is good...
Michael Ferguson
1959 TR3A TS53990L (soon to be "O")
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