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I acquired a Triumph 2500 gearbox with J type overdrive that I am rebuilding mainly to learn about gearboxes and also to have a rebuilt box for my TR6. Or maybe for my daily driver TR2 if or when it needs a new box.

This is the first time I've done a gearbox so will be greatly appreciative of advice from those with expertise.

I have acquired most of the bits I need and have started reassembly.

1st question. The end float for 3rd and 2nd gear is supposed to be .004 to .008". Mine both measure at the lower end of this range, the .004 feeler slides in easily and the .005 won't go in at all.

Is this OK? It is within specs but just.

2nd question. How do I get the big circlip at the front of 3rd gear on?

3rd question. How much force should be needed to separate the synchro hubs? I can separate them with a decent push with my thumbs.

Edited by John McCormack
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1 hour ago, John McCormack said:

I acquired a Triumph 2500 gearbox with J type overdrive that I am rebuilding mainly to learn about gearboxes and also to have a rebuilt box for my TR6. Or maybe for my daily driver TR2 if or when it needs a new box.

This is the first time I've done a gearbox so will be greatly appreciative of advice from those with expertise.

I have acquired most of the bits I need and have started reassembly.

1st question. The end float for 3rd and 2nd gear is supposed to be .004 to .008". Mine both measure at the lower end of this range, the .004 feeler slides in easily and the .005 won't go in at all.

Is this OK? It is within specs but just.

2nd question. How do I get the big circlip at the front of 3rd gear on?

3rd question. How much force should be needed to separate the synchro hubs? I can separate them with a decent push with my thumbs.

In my view you need to direct your question to Stuart who is a regular on this Forum and speak directly to ORS here in the UK, who re-con all makes of Gearbox's and have plenty of parts in stock. They are famous for O/D conversions on non O/D gearbox's. They are quite approachable!

Bruce.

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25 minutes ago, astontr6 said:

In my view you need to direct your question to Stuart who is a regular on this Forum and speak directly to ORS here in the UK, who re-con all makes of Gearbox's and have plenty of parts in stock. They are famous for O/D conversions on non O/D gearbox's. They are quite approachable!

Bruce.

Thanks Bruce. We have plenty of excellent gearbox people here including specialists on TR boxes. I'm slowly working through each issue as I come to it and am seeking advice from Australian specialists and Register members to get a broad range of views rather than rely on any one individual.

I know Stuart will provide very sound advice, as will a few others on here.

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John - if you want an accurate speedo , you will need to change the Speedo drive for a TR one (  15 inch wheels as opposed to 14”). You you also need to change the rear output flange for a TR one as the PCD of the saloon one is very slightly different - you can re- drill the saloon one to match but it has to be accurately done otherwise you will get vibrations and knock out your bearings very quickly .

If you retain the saloon input shaft, which is ok to do, simply carry on using the matching saloon clutch plate.

You could also consider tapping the top cover to take an extra inhibitor switch so you can have OD on 2nd as well, but don’t use a lot of welly in 2nd OD if you do.

l'm sorry I don’t have enough detailed technical knowledge to advise on the intricacies of rebuilding the internal parts but there are plenty of people here who will.

cheers Rich 

Edited by rcreweread
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2 hours ago, John McCormack said:

I acquired a Triumph 2500 gearbox with J type overdrive that I am rebuilding mainly to learn about gearboxes and also to have a rebuilt box for my TR6. Or maybe for my daily driver TR2 if or when it needs a new box.

This is the first time I've done a gearbox so will be greatly appreciative of advice from those with expertise.

I have acquired most of the bits I need and have started reassembly.

1st question. The end float for 3rd and 2nd gear is supposed to be .004 to .008". Mine both measure at the lower end of this range, the .004 feeler slides in easily and the .005 won't go in at all.

Is this OK? It is within specs but just.

2nd question. How do I get the big circlip at the front of 3rd gear on?

3rd question. How much force should be needed to separate the synchro hubs? I can separate them with a decent push with my thumbs.

That end float is fine, never re-use that big circlip always use a new one and its always a difficult one to fit, usual way is two large screwdrivers. Sounds like those synchro hubs will be OK, its usually second gear ones that suffer the most wear so if you need then re-use s/hand 4th gear ones in their place.

Stuart.

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1 hour ago, John McCormack said:

Thanks Bruce. We have plenty of excellent gearbox people here including specialists on TR boxes. I'm slowly working through each issue as I come to it and am seeking advice from Australian specialists and Register members to get a broad range of views rather than rely on any one individual.

I know Stuart will provide very sound advice, as will a few others on here.

Note: ORS has the Volvo contract to re-con their O/D's at over 300 per annum, they also make the parts on GKN's original m/c's for o/d's and gearbox's. Their has been quality issues with many of the gearbox parts over the last 30 years from other sources and I had a bad experience 3 years ago?

Bruce.

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There have been plenty of rubbish new synchro's. One theory was that when clamped for machinging they were distorted.

When released they spring back to a different shape to that which was machined on them.  Cheap garbage.

The question for many is who to go to to get decent synchro's.

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Then there were the synchros that were machined too big and when all four were in place the mainshaft just locked up, I filed some of the rear pads down, but you could get away with using one old synchro and putting it on 4th gear, ..... as to where to go for new ones that's anybody's guess, but forget the cheap ones, it's worth checking old ones on a new gear cone to see if they've not worn too much and could be reused.

Cheers Rob

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Thanks gents.

I've finished the end float tolerances and all are within spec, some near the extremes but still OK as Stuart advised above.

I've got the Buckeye and a couple of other documents next to me while I do the box but they are always written with the idea the reader has some knowledge. Not being familiar with the process it therefore takes a bit of trial and effort to figure out what is meant. I'm getting there.

I've this morning been told my lay gear is beyond repair. I should be able to buy a good 2nd hand one locally. I thought about going to the uprated lay gear with the double roller bearing but it will cost me a fortune and I figure an uprated fully hardened layshaft and the later caged roller bearing will be adequate for my purposes.

I made a mistake buying a full overhaul kit for the gearbox as I won't be using the laygear roller bearings and the synchros in the box were well within tolerances. I'll use the new synchros anyway, they have been checked by my Triumph man who says they are good ones. I will need to itemise what I need for the overdrive, O rings, bearings etc and only get what I need.

I will be changing the speedo drive to have the speedo read correctly on whichever car this goes into. The TR6 has a 2500 J type box in it now so I am assuming it has a 2500 clutch plate.

I actually don't need a rebuilt gearbox right now but with over 40 years of TR ownership I had never rebuilt a gearbox so this is largely a learning exercise. I do have 3 TRs in the garage so a spare os gearbox will be handy to have.

In time the box should go into the TR6 but it might go into my daily driver TR2. I have been advertising the 6 for sale but with the lockdowns not much has been able to be done on the sale, and every time I drive it I change my mind on selling it.

I am sure I'll have more obstacles to this rebuild. It is my first time so I will make mistakes and find issues like my laygear being u/s.

With the advice from this forum and my Australian mates and specialists I should end up with a excellent gearbox and od.

 

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On 10/9/2021 at 2:45 AM, John McCormack said:

Thanks gents.

I've finished the end float tolerances and all are within spec, some near the extremes but still OK as Stuart advised above.

I've got the Buckeye and a couple of other documents next to me while I do the box but they are always written with the idea the reader has some knowledge. Not being familiar with the process it therefore takes a bit of trial and effort to figure out what is meant. I'm getting there.

I've this morning been told my lay gear is beyond repair. I should be able to buy a good 2nd hand one locally. I thought about going to the uprated lay gear with the double roller bearing but it will cost me a fortune and I figure an uprated fully hardened layshaft and the later caged roller bearing will be adequate for my purposes.

I made a mistake buying a full overhaul kit for the gearbox as I won't be using the laygear roller bearings and the synchros in the box were well within tolerances. I'll use the new synchros anyway, they have been checked by my Triumph man who says they are good ones. I will need to itemise what I need for the overdrive, O rings, bearings etc and only get what I need.

I will be changing the speedo drive to have the speedo read correctly on whichever car this goes into. The TR6 has a 2500 J type box in it now so I am assuming it has a 2500 clutch plate.

I actually don't need a rebuilt gearbox right now but with over 40 years of TR ownership I had never rebuilt a gearbox so this is largely a learning exercise. I do have 3 TRs in the garage so a spare os gearbox will be handy to have.

In time the box should go into the TR6 but it might go into my daily driver TR2. I have been advertising the 6 for sale but with the lockdowns not much has been able to be done on the sale, and every time I drive it I change my mind on selling it.

I am sure I'll have more obstacles to this rebuild. It is my first time so I will make mistakes and find issues like my laygear being u/s.

With the advice from this forum and my Australian mates and specialists I should end up with a excellent gearbox and od.

 

I would be very wary on lay shafts? For years here in the UK we were supplied with soft ones and this was where I nearly got caught out. Having severed a toolmaking apprenticeship I did the file test on the one supplied by Moss and I could file a flat on the edge of, it was soft! This was confirmed when they did a Rockwell hardness test. I don't know where the Australian ones come from? It is also important to check the O/D of the shaft as there has been problems there as well of beaning undersize?

Bruce.

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12 hours ago, astontr6 said:

I would be very wary on lay shafts? For years here in the UK we were supplied with soft ones and this was where I nearly got caught out. Having severed a toolmaking apprenticeship I did the file test on the one supplied by Moss and I could file a flat on the edge of, it was soft! This was confirmed when they did a Rockwell hardness test. I don't know where the Australian ones come from? It is also important to check the O/D of the shaft as there has been problems there as well of beaning undersize?

Bruce.

Thanks Bruce.

I bought a hardened shaft from our local Triumph man. We are fortunate in that he is Triumph through and through having done his apprenticeship with the Standard Triumph industry in the 60s. He is a key member of the largest Triumph club (Triumph Sports Owners Association) and has a reputation to uphold. He doesn't do rubbish.

These shafts are hardened through, not just case hardened. I have found a good laygear from another local Triumph man which is already fitted with the caged roller bearings. 

Looking good until the next challenge appears.

 

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Hi there,

the lack of hardness is a big problem.
In addition, the laygear axis do not have the correct diameter. Too small You can test wonderfully with a piston pin from the TR 6. That would be the master. I think the best source for laygear axis is the Roadster factory in USA. Until now, they always had the correct diameter, hardness and surface quality.
I've already had parts in my hand that were only turned and not precision ground! Cruel, sent right back. Or scrap buckets.
Also A Type Annulus,
which are in the trade have no hardening !!!!!
Do the simple file test.

Best regards
Ralf

Edited by Schnippel
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4 hours ago, Kenrow said:

This is for a Type A OD but interesting overview...

https://www.youtube.com/watch?v=cgNadKy16QE

 

+1

If anyone hasn't seen Elin Yakov's YouTube videos, I highly recommend it. He has restored several TR's and has pretty much filmed everything as he does a body-off restoration. That includes panel work, engine/gearbox overhauls and everything in-between. The only missing bit is the PI system as he is living in Canada.

I have no affiliation with Elin, but think he deserves a lot of praise for giving people (i.e. me) the confidence to tackle a projects that I would have previously sent to the workshop. Not that I have that option anyway now as I live in France and TR specialist here are thin on the ground.

Cheers, Robert

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9 hours ago, John McCormack said:

Thanks Bruce.

I bought a hardened shaft from our local Triumph man. We are fortunate in that he is Triumph through and through having done his apprenticeship with the Standard Triumph industry in the 60s. He is a key member of the largest Triumph club (Triumph Sports Owners Association) and has a reputation to uphold. He doesn't do rubbish.

These shafts are hardened through, not just case hardened. I have found a good laygear from another local Triumph man which is already fitted with the caged roller bearings. 

Looking good until the next challenge appears.

 

It is common practice over here to bore out the lay-gear bore to fit a third needle roller caged bearing as per Stag gear box. for TR's, as this dramatically increases the life of the layshaft. I had this mod done!

Bruce.

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Hi there,
Unfortunately, the use of a third needle bearing is only limited to certain km / ml, as you can see on the picture. Mileage approx 12,000 km. No correct hardness and diameter of the laygear axis and the destruction begins. As some know, the entire gear box must be meticulously cleaned of fine metal particles. Needle roller bearings are very, very sensitive to dirt.

Best regards
Ralf

1717338987_VorgelegeSchadenmitDreiLagern.thumb.JPG.0a654c261f20bd3a50567fcae175942f.JPG

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3 hours ago, Schnippel said:

Hi there,
Unfortunately, the use of a third needle bearing is only limited to certain km / ml, as you can see on the picture. Mileage approx 12,000 km. No correct hardness and diameter of the laygear axis and the destruction begins. As some know, the entire gear box must be meticulously cleaned of fine metal particles. Needle roller bearings are very, very sensitive to dirt.

Best regards
Ralf

1717338987_VorgelegeSchadenmitDreiLagern.thumb.JPG.0a654c261f20bd3a50567fcae175942f.JPG

I would be interested to know if you still have that shaft does it pass the file test on the edge or what is the Rockwell hardness on the C scale in an unworn area?

Bruce.

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Hello Bruce,

the owner of the gearbox has the laygear shaft back.
As always, I did a file test ...... insufficient hardening.
Many greetings
Ralf

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3 hours ago, Schnippel said:

Hello Bruce,

the owner of the gearbox has the laygear shaft back.
As always, I did a file test ...... insufficient hardening.
Many greetings
Ralf

Ralf I did fully understand you last but one thread? Are saying that a modified lay gear with 3 needle rollers does not work as I have done over 12000 miles with my modified one and have had no problems! My lay shaft was bought from ORS here in the UK. But I do no know if they only case harden them or use a steel that you can fully harden to the core. 

Bruce. 

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Hello Bruce,
the three needle bearing variant works. Provided that the hardness and diameter are suitable.
Best regards
Ralf

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On 10/11/2021 at 8:07 PM, astontr6 said:

It is common practice over here to bore out the lay-gear bore to fit a third needle roller caged bearing as per Stag gear box. for TR's, as this dramatically increases the life of the layshaft. I had this mod done!

Bruce.

I picked up the laygear today and it has the uprated roller bearings in it already. I have a fully hardened layshaft so will go with this setup.

While the double roller bearing is a common upgrade here I'm told there have been cases of the laygear itself failing where it has been bored out to take the 2nd bearing.

My car isn't raced or driven overly hard, spirited but not stupidly. As the combination I have is a major improvement on the original I'm comfortable with it.

Now I have the good laygear the float is down to 7-8 thou (it was 14 thou with the old worn out laygear) which is the minimum recommended in the Buckeye advice. I'm pleased with that.

 

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3 hours ago, John McCormack said:

I picked up the laygear today and it has the uprated roller bearings in it already. I have a fully hardened layshaft so will go with this setup.

While the double roller bearing is a common upgrade here I'm told there have been cases of the laygear itself failing where it has been bored out to take the 2nd bearing.

My car isn't raced or driven overly hard, spirited but not stupidly. As the combination I have is a major improvement on the original I'm comfortable with it.

Now I have the good laygear the float is down to 7-8 thou (it was 14 thou with the old worn out laygear) which is the minimum recommended in the Buckeye advice. I'm pleased with that.

 

Based upon my engineering back ground I have always had suspicions that part should be fully harden right through and not case hardened?. I will pursue that here in the UK.

 

5 hours ago, Schnippel said:

Hello Bruce,
the three needle bearing variant works. Provided that the hardness and diameter are suitable.
Best regards
Ralf

The issue for me now is that this part s/b fully hardened right through which means a change of material and not case hardened as grinding to size will remove the hardness layer. There has been many instantances of this here in the UK.

Bruce.

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John

apologies to sneak in on your thread but also interested in the gbox

i have been reading this as i will be reviewing my box as part of the rebuild nothing wrong with it when it went off the road 28 yrs ago but will need stripping checking etc etc

lay shaft was one to sort however cna anyone advise if just normal use (ie shows occasional meetings and the IWE) is the original way just as good

i find a lot of extra add on's these days which like the rocker feed kit not required if the cyl head rocker shaft is sorted

i ran my 5 when in my early twenties therefore red line nearly everytime and never had any issues (probably fall to bits now i jinxed it)

just looking for thoughts

david

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11 hours ago, John McCormack said:

I picked up the laygear today and it has the uprated roller bearings in it already. I have a fully hardened layshaft so will go with this setup.

While the double roller bearing is a common upgrade here I'm told there have been cases of the laygear itself failing where it has been bored out to take the 2nd bearing.

My car isn't raced or driven overly hard, spirited but not stupidly. As the combination I have is a major improvement on the original I'm comfortable with it.

Now I have the good laygear the float is down to 7-8 thou (it was 14 thou with the old worn out laygear) which is the minimum recommended in the Buckeye advice. I'm pleased with that.

 

I have able to get hold of the old BL spec. for materials and heat treatment for GB layshafts!

The grade of steel is EN36 which is a high strength case hardening grade with a high depth of hardening. Minimum hardness to be .020" and the surface hardness to be 60 Rockwell on the C scale. A fully through hardened bar of steel is not recommended as it has no flex? Please can you run these details across your gearbox man for comments.

Bruce.

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