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Fitting a saloon gearbox to a TR3a


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It's all too easy for latter day enthusiasts to imagine that Standard Triumph was staffed by engineers of limited competence, and accountants of even lesser talent. Unfortunately, that is an incorrect concept - especially once the Leyland bean counters had moved in.

 

If saloon gearbox and overdrive fitments had been adequate for TR application, that is what would have been utilised. But they were not adequate, which is why TR units continued to be specified.

 

If you drive your TR at Vanguard pace, then fair enough a saloon fitment will handle the situation. If you drive the TR like it should be driven, then don't expect longevity from a saloon transmission. Or, for that matter, satisfactory gear ratios.

 

A saloon o/d box is merely the basis for a specialist to convert (at a not inconsiderable cost) to TR spec, it's not in itself an adequate substitute for a pukka TR unit - no matter how much you fiddle and twiddle with peripherals.

 

 

Cheers,

 

Alec

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Just to clear up a few points, - the saloon box and overdrive was a virtual freebie.

 

ORS overhauled and rebuilt the OD to TR spec for £500 which included a new rear cover so that it would accept the standard TR rear mounting.

 

The OD ratio is 22%

 

I had the main gearbox checked by a local transmission specialist and they replaced a bearing but said everything else was fine. Cost £150.

 

Put this against the cost of having my original TR box checked/overhauled and then adding an overdrive and it looks like a bargain. Unless you are the very lucky person who bought the TR box plus OD for £600 from the bring and buy stall at the recent IWE.

 

Rgds Ian

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I am new to overdrives but the reason most people want them is that the original ratios on a TR box don't suit some modern driving situations e.g . Getting to Malvern from Scotand, orlonger journeys to the Continent.

 

Plus the weight and power of a 2000, 2500 etc must involve stresses as high as a TR2/3/3A?

 

I did not want to spend £1000 to get an overdriveand I doubt I could have got an original TR OD box for that any way

 

Bill G @ NB

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  • 4 months later...

Hi all.

I also intend fitting a T2000 gearbox + overdrive to my TR3. (after I've finished the rebuild)

It seems the choices of clutch are:

Use T2000 driven plate with TR3 pressure plate, & TR release bits including changing the carrier sleeve to TR

Use T2000 driven plate with T2000 pressure plate & T2000 release bits, but drill flywheel to suit.

 

The solenoid need a different bracket to mount it vertically

 

Longer bolts required to fit bell housing to engine as bell housing flange is thicker

 

I am not clear on whether any changes are required to the rear gearbox to chassis mounting

 

Any advice on this would be welcome

 

Cheers

Bob.

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You can use the T2000 driven plate with the TR pressure plate even though it is slightly smaller than the TR driven plate, but you need to swap over the Nose (Clutch release bearing carrier) and fork from the TR box as the T2000 release bearing is too small and will jam in the fingers of the pressure plate( the 3 finger type) these parts are a direct swap, if you feel like it you can also replace the oil seal in the nose at the same time but it is a pig to get out.

 

Cheers

 

Alan

Edited by Kiwifrog
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  • 1 year later...

The saloon input shaft will fit the flywheel centre bush OK, but the splines are different (more of them) to TR ones,

so you need the saloon clutch driven plate.

Also check that the clutch release fork matches the release bearing as mentioned above.

 

Bob.

 

P.S.

 

Mine is all up & running now, I went for a GT6 complete clutch, which is compatable with T2000 etc. I had to re-drill the flywheel to take the cover plate as it is slightly smaller. I kept all the T2000 gearbox release mechanism. The overdrive did not work anyway, so I had that re-built by a local specialist, & they changed out the rear casing so as to be the same as TR. the only remaining problem was the speedo drive, Saloons use a ratio of 3.5:1 whereas TR's use 2.5:1 This makes for a large speedo error. I solved this by (after lots of maths, & web searching) by obtaining a speedo from a Mk2 T2.5P.I. which had the required turns per mile of 850. I installed the innards of the T2.5 speedo inside the shell of the TR one, all fitted remarkably well considering the age differance. A cross check using GPS showed it to be almost spot on !

 

Good luck with your fitment

 

Bob.

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Bill,

 

If it has a horizontal solenoid (it is actually an electromagnitic switch) it is a J-type box. I have succesfully fitted them to a TR6 and to my current TR3A. It is an excellent and strong box with box slightly better ratios than the original.

 

I just needed an appropriate friction plate, using the original cover from my TR. No snags with the slave cylinder or the release fork, which I cross drilled and through bolted as a precaution.

 

The overdrive should have a plate on it which will tell you that it is a J-type. Its serial number should start with either 23, 25 or 28/ .....which indicates the percentage of gearing improvement of the overdrive - i.e the higher the better.

 

The only other mods needed are the gearbox drive flange which will have to be re-drilled to fit the TR propshaft and it might (Triumph 2000 but not the PI) need a little machining off the centre recess as well. Finally, You'll need a rear mounting bracket for the chassis. Moss do it for about £100.

 

My J-type is really excellent with a super smooth change and is a very worthwhile and invisible mod. I don't understand your comment about moving the "solenoid" to vertical as it is unnecessary and I think impossible. The gearbox and overdrive will fit as they are.

 

Good luck,

 

Willie

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Hello Ian if you get a borg@beck 47626/53 or 47418/63 this gives you correct center for saloon box with a 9" outer if not i had a couple made via a jumbler at Newark i think he called JCL but not 100% its 15yrs ago he has a saloon center made up with a TR 9" outer this gets round all them carrier and bearing problems, i have also messed around with fitting first motion shaft from TR in saloon box,as i remember shaft needs boring and a bronze bush making instead of the roller bearing same as an early TR2 this same opperation can be done to fit a saloon mainshaft into TR box. This has probably confused you even more sorry Martin.

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  • 3 years later...

If it has a horizontal solenoid (it is actually an electromagnitic switch) it is a J-type box.

 

 

 

Saloon A type OD gearboxes also have an horizontal solenoid.

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The saloon input shaft will fit the flywheel centre bush OK, but the splines are different (more of them) to TR ones,

so you need the saloon clutch driven plate.

Also check that the clutch release fork matches the release bearing as mentioned above.

 

Bob.

 

P.S.

 

Mine is all up & running now, I went for a GT6 complete clutch, which is compatable with T2000 etc. I had to re-drill the flywheel to take the cover plate as it is slightly smaller. I kept all the T2000 gearbox release mechanism. The overdrive did not work anyway, so I had that re-built by a local specialist, & they changed out the rear casing so as to be the same as TR. the only remaining problem was the speedo drive, Saloons use a ratio of 3.5:1 whereas TR's use 2.5:1 This makes for a large speedo error. I solved this by (after lots of maths, & web searching) by obtaining a speedo from a Mk2 T2.5P.I. which had the required turns per mile of 850. I installed the innards of the T2.5 speedo inside the shell of the TR one, all fitted remarkably well considering the age differance. A cross check using GPS showed it to be almost spot on !

 

Good luck with your fitment

 

Bob.

I am forever amazed at the ingenuity of TR owners to get any combination of unmatched components to eventually work together in a reasonable manor.

What worries me or even scares the hell out of me is that one day these vehicles will be passed on to new owners who will in the fullness of time discover that when a part of their pride and joy wears out they can find nothing off the shelf which is a direct replacement for the defunct part.

Exchange speedo, "sorry sir we cannot exchange your unit it is not out of a TR"

 

Now if the true provenance of the car is passed on to the new owner and it is priced according then fair enough. But personally I would be more than disappointed if I bought a TR and found out later it was not a 'real' TR but more of a bitza in a TR body.

Chris

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Chris,

 

When I bought my car it had already had a variety of different bits fitted to it - not unusual for a car that was nearly 50 years old and clearly well used. I rebuilt it to suit me and I am not a concours merchant so it has what is effectively a TR4a engine, an advance autoelectrics powerblock loom, R & P steering and a 3.45:1 rear axle. Oh and an overdrive box from a saloon.

 

All of my modifications are pretty well documented and if whoever buys it (as, when and if I decide to sell it) , wants to revert to standard spec, there is nothing that can't be undone.

 

For all of my changes, I still consider that it is a real TR with the original body shell and chassis and gearbox apart, matching numbers.

 

Rgds Ian

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A thought...

 

Earlier in this thread, someone suggested that this would make a good article for the TR Action. Is that still the case? In which case I might get around to pulling something together.

 

Rgds Ian

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Ian, about your saloon od gearbox, was it from a 2000 ? As far as I know, 2000 A Type od gearboxes are fitted with a 4 spring od clutch mechanism, compare to the 8 springs used in TR2 to 6 and 2500 saloon.

 

If it is a "4 springs" saloon od, how does it hold the engine torque ?

Edited by Chris59
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I can confirm that only 4 springs are used in saloon O/D's Mine was re-built with 8 plust the rear casing was changed for an Austin Healey one (same as TR)

 

Outstanding problem was the different speedo drive ratio, which would have needed a change in O/P shaft - which would have cost too much !

 

Bob.

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Ian, about your saloon od gearbox, was it from a 2000 ? As far as I know, 2000 A Type od gearboxes are fitted with a 4 spring od clutch mechanism, compare to the 8 springs used in TR2 to 6 and 2500 saloon.

 

If it is a "4 springs" saloon od, how does it hold the engine torque ?

I think I mentioned earlier that I had the overdrive rebuilt by ORS and they uprated it to TR spec with 8 springs and a higher capacity pump (I think) as well as fitting a Tr rear casing and output flange so that it was s drop in replacement for a TR box.

 

Rgds Ian

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