5-speed conversion for a 1937 TA

[bergxu]

Hi gents,

So, have been making some improvements to my recently acquired ‘37 TA (new hood and side curtains, five new 4.5x19 Excelsior tires and tubes) and have been contemplating a 5 speed swap. Those of you who helped me vet this car on my other thread will recall that it’s fitted with an XPAG engine although I’m unsure if it still has its original gearbox or not (how can I physically tell the difference between them?). Anyways, I saw the kit that Hi Gear Engineering sells but his website says it’s for the TB and TC. Any reason why it can’t be fitted to the TA?

Also, my recently departed ‘48 TC’s gearbox worked beautifully and this car seems to have a weak second gear synchro (or it’s still a non synchro 2nd gear TA box, I don’t know!). But that’s my main reason for considering the 5 speed, I’d like a little better in town drivability and not having a good 2nd gear synchro really detracts from being able to enjoy the car….unless this can be fixed? No idea if parts are even available and/or who could refresh the box? Thoughts on all of the above of course appreciated!

Aaron

[Steve Simmons]

The easiest way to tell the difference is by the aluminum extension on top. Here are photos of TA (found on the web) and TC.

No experience with 5-speed in a TA, sorry!

[bergxu]

Thank you Steve. I’ll have to take a look and see which box is in the car. Appreciate the pics.

I do love the “rifle bolt” feel of the original T boxes but it seems that getting them repaired is difficult to impossible.

Aaron

[Steve Simmons]

I'd think that any old school transmission shop could do it. They really aren't that complex. The only challenge is finding certain parts. We're rebuilding a TC box right now. We had it apart in about an hour, although my "helper" has rebuilt countless old British gearboxes so it's going much faster than I could do on my own.

[bergxu]

I’m thinking the synchro rings aren’t available or reproduced any longer but I could certainly be mistaken. If I knew I could have the box that’s currently in the car redone, I’d be happy to go that route. I switched the gear oil in my ‘48 TC to Redline 85W-140 and man that car shifted beautifully. Was going to try that first in this car but my gut tells me it’s going to need an overhaul at the end of the day.

[Steve49TC]

The Octagon Car Club (bi?)monthly magazine ran a really good engineer-written, blow-by-blow, colour illustrated account of a chap putting a type 9 five-speed in his TA. The saga ran over two or three editions, only last year I think. If you are interested contact the club and ask to buy the back-issues.

My impression was that the gentleman ran into a lot more difficulties than expected but was an absolute perfectionist.

If simpler solutions are possible you might glean them from his writing , or at least know exactly what to do to follow his final solution.

[Steve49TC]

Oh, just spotted you have an XPAG. The Octagon articles were to mate Ford box to MPJG. Still might help you for gearbox mounts and details.

I have both the 5-speed AND a 4.625:1 diff and although I have only driven them 150 miles, and those rather gentle miles as I'm running in the new engine, I am really pleased. I mention it as I think your TA will have a high ratio back axle already?

First isn't too high, it feels just normal, and she'll accelerate out of a 30 limit in 5th quite happily and was a relaxed joy to potter through the lanes to Gaydon for the 100th anniversary do. It's a 1350 XPAG with a slightly longer cam.

[bergxu]

Appreciate that info Steve. I’m going to first see if some Redline 85W-140 will improve things with the existing box but if not, I’ve gone ahead and reached out to Hi Gear to open communications on obtaining a kit.

[Ray White]

The TA rear axle has an 4.875:1 gear ratio (8/39) which is a bit lower than in Steve's car. The standard 1st gear in the T9 box is even lower than the first gear found in the TC box. Because of this I would suggest you take up the offer of a higher 1st. gear which Peter Gamble can fit to in the T9 (Ford) box. I have a 'Hi Gear' 5 speed conversion with a modified (higher) 1st gear and a TA cw & p. I am hopeful - when it's eventually on the road - the Eaton supercharger will have enough grunt to pull it.

Incidentally, I live fairly close to Peter Gamble and have had very satisfactory dealings with him. He has helped me through a few problems with my restoration and I would highly recommend him.

[bergxu]

Thanks Ray, yes, Peter has been quite helpful thus far in my communications with him and I agree the alternative 1st gear ratio is a good idea so will have it built that way. I’ve been working on my Healey 3000s and my MGB/GT the last couple of weeks so will be resuming work on the TA in just a bit and need to send Peter some measurements….he asked me for the distance from the face of the gearbox output flange to the face of the axle input flange as he has seen variations so wanted to make sure that is known on my car before a kit is assembled.

Aaron