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Mystery gearbox


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Hello. Can anybody solve my mystery? I am restoring  a CF model and have just bought an OD gearbox which was said to be from a saloon. It has an A type unit fitted with a flat crossmember as expected. What puzzles me is the identification letters and numbers. They are very clear and large, and located in the correct place, but I cannot find any information about them in the triumph 2000+2500 genuine workshop manual. The letters are as follows- EX    COM     17   I would love to know what I have bought!.

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The only number I recognise is the 22 in the second photo, it means its a 22% overdrive, there could be some with 28 = 28%

Internal parts could be changed to give the higher ratio.

John

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Hi - the smaller number 69 on the gearbox is almost certainly its casting date, but I'm not sure why there is a hole in the casting next to the number in your photo - similar holes were found in early 4 pot gearboxes where the cross shaft was located by a bolt through the casing but this was way before 1969.

I don't recall ever seeing a gearbox number anything like yours - I can only assume it might be a factory replacement part.

Re the overdrive, I have looked at my data sheets and cannot find the "61916" serial number anywhere - this is the part of the serial number which denotes the model the OD was supplied to  - as already stated, the 22 related to the reduction ratio.

I suggest you contact Overdrive Spares in Rugby re the OD and ORS in Sheffield re the gearbox -I'm sure they may be able to throw some more light on the case.

In the meantime, some photos of the whole unit would help.

Cheers Rich

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In Australia in the 1960's EX was typically stamped on rebuilt exchange changeover equipment. Ie in the case of a gearbox, you supplied your old gearbox to the rebuilder who gave you an off the shelf replacement stamped EX so that subsequent owners would know it was rebuilt.

But that might have been a local convention?

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Dieter, I believe that EX did indeed designate experimental from the factory. have a word with Dave Pearson at Canley Classics as he has a lot of information on experimental parts and pretty sure that he also has one of the 5 speed gearboxes.

Derek  

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7 hours ago, SeidelVC69 said:

I am owning this gearbox which I am planing to restore in the near future. It`s a 5 speed Triumph gearbox and I was informed

that there are only 5 or 6 of it produced probably for EXperimental use? Does it explain the EX letters on it? Dieter

 

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Canley Classics have one too.  Theirs has a saloon mounting yours has a TR.  By serial number - yours is gearbox no 2 theirs is no 1

https://www.canleyclassics.com/?archive=5-speed-gearbox

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Hi All

Makes interesting reading, completely unaware there was a 5 Speed development of the Triumph gearbox.

When were those experimental ones made, was it then end of the TR6 run or early on?

In terms of it being better than the LT77 I have no idea but can see the attraction of a modular gearbox with a bolt on bell housing and rear case, it would seem to make it easier to fit the same basic box to different vehicles, esp if it were already designed and on the shelf as it were.  With the Triumph box it would seem the whole casing would need to be different if a different sized (esp shorter) bell housing was needed.

Bet those experimental boxes are now worth a pretty penny, more than my car, lol.

Cheers  Keith

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Hi, I have here more photos as requested. Sadly I doubt my box is anything special, very likely exchange. At one point in my career I worked for a main dealer where I had to rebuild a steering box with a new casing rather than simply fit a new box because it would save eight pounds! Maybe that happened with this box whilst under warranty? I will let you know if it turns out to have 5 gears and overdrive as well! Regards Alan.

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2 hours ago, Coops said:

Hi, I have here more photos as requested. Sadly I doubt my box is anything special, very likely exchange. At one point in my career I worked for a main dealer where I had to rebuild a steering box with a new casing rather than simply fit a new box because it would save eight pounds! Maybe that happened with this box whilst under warranty? I will let you know if it turns out to have 5 gears and overdrive as well! Regards Alan.

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Certainly looks like a saloon box with the smaller input shaft and the crossmember in the background, and fitted with what looks like an A type overdrive - strange that there are no inhibitor switches on the top cover though it looks like the reversing light one on the side has been removed so maybe a top cover has been fitted from a non overdrive box. The only other thing which looks a bit strange is the adapter plate between the OD and the gearbox which is normally aluminium. I'm sure someone told me that the works rally cars changed this alloy plate for a steel one as they had a tendency to warp/bend - the adapter plate in the photo looks thicker than an alloy one and it looks rusty indicating that its steel/iron so maybe there is a bit of strange history going on?!

Cheers Rich

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30 minutes ago, rcreweread said:

Certainly looks like a saloon box with the smaller input shaft and the crossmember in the background, and fitted with what looks like an A type overdrive - strange that there are no inhibitor switches on the top cover though it looks like the reversing light one on the side has been removed so maybe a top cover has been fitted from a non overdrive box. The only other thing which looks a bit strange is the adapter plate between the OD and the gearbox which is normally aluminium. I'm sure someone told me that the works rally cars changed this alloy plate for a steel one as they had a tendency to warp/bend - the adapter plate in the photo looks thicker than an alloy one and it looks rusty indicating that its steel/iron so maybe there is a bit of strange history going on?!

Cheers Rich

The steel plate is common to A type 

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1 minute ago, ntc said:

The steel plate is common to A type 

Are you sure ? All the J type OD boxes I've seen have a steel adapter plate and the A types an alloy one

Cheers Rich

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My apologies for using wrong terminology and causing confusion - the adapter on an A type OD I was meaning is an alloy machined casting with part number 208098 and is referred  to in the Moss catalogue as "Adapter, overdrive to gearbox" and I can guarantee this is normally alloy. It is this part which I understand caused problems in the ST competition cars and was substituted with a stronger steel version and which, if you look carefully at the photos in this post, looks rust coloured and thicker than the alloy plate. 

The part in a J type I was referring to, is actually termed the "brake ring"  and is part number NKC10 and this is steel/cast iron ( not sure which), and is a part connecting two sides of the overdrive unit together, and visible externally as a narrow steel band, which is often rusty. The "adapter" in a J type is a substantial casting and is indeed alloy, so this is presumably where post comments above are aimed. Sorry for the confusion.

If indeed this was an experimental competition part, it would appear to be numbered 17 and was cast in 1969 so presumably could have been for the rally saloons - taking this through to the OD serial number, 22/61916/12 , as I have previously said, I can't find "61916" as a recognised model ID - the nearest I can find is 61973 which was for 2.5 PI saloons from 7/68 to 11/72 , 61977 which was for Stags from 11/69 to 11/72 and 61985  which was for TR6 from 4/71 to11/72 so maybe this was created specifically for a short run of competition units and the very low quantity sequence of "12" as are the last digits could also point to this - the plot thickens!

Cheers Rich

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12 hours ago, ntc said:

The steel plate is common to A type 

Thats the rear plate to the tail section, the main adaptor plate to the box is alloy. The pictured one has a steel adaptor plate to the box. Ive seen a fair few of the ally ones cracked or warped.

Stuart.

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