View Full Version : TR2/3/3A TR3B Transmission?

03-31-2012, 12:06 PM
I recently bought a 1960 TR3A which came with a spare engine and transmission. The spare engine is for a TR3B (TCF 103E). The spare transmission number is TS 74635. Is there an easy way to tell if this is a TR3B transmission (syncro for first gear)?

03-31-2012, 12:24 PM
Doesn't it seem more likely that it is the original box for your 60? How close is the box number to the comm# for the car?

03-31-2012, 12:52 PM
I believe that I have all original in my 1960 TR3. This is a spare transmission that came with the car. If it goes with the spare engine, then it is for a TR3B. I'm wondering if there's an easy way to tell.


03-31-2012, 02:40 PM
Pop the top cover and look at the gears. If the first gear (the rearmost) teeth are straight-cut, it's a three syncro. If the first gear teeth are helical, like 2 & 3, it's a four syncro. From the number you gave, I'm betting it's a three syncro.

Andrew Mace
03-31-2012, 04:22 PM
Just a guess, but I'd assume a gearbox with a TS prefix would be 3A. I'm not sure what the gearbox numbering was for the 3B, but I'd guess it would've been CT prefix.

03-31-2012, 05:16 PM
Another check is to look at the side of the gearbox. If it has synchro 1st, there is a large cylindrical bulge on the LH side, which is (just) visible at the bottom of this photo:

The 3 synchro box is more nearly flat:

03-31-2012, 05:42 PM
There are two series of TR3Bs. The early version was TSF and the later one was TCF. Before I stated the differences, I checked some of the books in my library.

According to Piggott’s “Original Triumph TR2/3/3A” the TS series had basically a TR3A drive train. This would imply that they would have a non-synchro first gear. Piggott's book says that the TCF series had the basically a TR4 drive train including the full synchro gear box. The “Illustrated Triumph buyer’s guide” by Richard Newton agrees with Piggott about the engines, but states that both versions had full synchro gear boxes.

Not all of the TCF cars had the 2138cc engines. A few months ago I exchanged some emails with another TR3B owner who’s car had been ordered with a 1991cc engine.

My car, TCF5##L does not have the original engine, but I think its transmission is original. Its serial number starts with a TSF. This would tend to support the idea that at least some of the TSF cars had full synchro gear boxes.

03-31-2012, 05:58 PM
Graham Robson also stated the TSF cars had (mostly) the 4-synchro box.

FWIW, the 2138 engine became optional during the TR3A run. Then the options were swapped, so the 2138 became standard; but I believe the 1991 option remained through the TR4 & 4A.

Andrew Mace
03-31-2012, 06:29 PM
As I implied before, I don't think the gearboxes got any unique prefixes. The original 1991cc engine for the 3B carried a TSF prefix, while the 2138cc engine had a TCF prefix. For the TR4, "normal" (2138) engines were CT, while the optional 1991 was CTA prefix as I recall.

04-01-2012, 11:22 AM
Thanks to all - Mystery solved. It'a a TR3A tranny. No round bulge on the left hand side and I opened it and took a look at the gears to verify. Having syncro in first is so the 60s anyways.