Triumph gearbox differences.

[Malbaby]

I have a TR4 4 speed gearbox and a 2500 sedan overdrive gearbox in my garage.

The input shaft diameters are different....enlightenment please.

Edited December 18, 2023 by Malbaby

[Z320]

Take the TR4 gearbox!

[John Morrison]

just so, 

Saloon box input shafts are different diameters, saloon is smaller.

Plus spigot bush, if you want to run the saloon box you need the TR clutch housing for the TR flywheel, but the saloon driven plate 

for the saloon input shaft, know cars that have run this way for twenty years or so.

Differences at the output end, O/D Tail casing is different,  Chassis mount is different as is the internals of the O/D its weaker than the pukka TR one, and the 

output flange hole pattern is different to the TR one.

Sure there are more, but these are the main ones I think.

John.

[rcreweread]

8 minutes ago, John Morrison said:

just so, 

Saloon box input shafts are different diameters, saloon is smaller.

Plus spigot bush, if you want to run the saloon box you need the TR clutch housing for the TR flywheel, but the saloon driven plate 

for the saloon input shaft, know cars that have run this way for twenty years or so.

Differences at the output end, O/D Tail casing is different,  Chassis mount is different as is the internals of the O/D its weaker than the pukka TR one, and the 

output flange hole pattern is different to the TR one.

Sure there are more, but these are the main ones I think.

John.

Also the speedo drive is for 14" wheels, so the speedo will be inaccurate.

By the way, is it an A or J type overdrive? Can you post the serial numbers of the OD?  They should be stamped on a plate riveted to the body of the OD. If it's a J type, the reduction ratio is likely to be 25% but could be 28% - the serial number will reveal

cheers Rich

[Lebro]

You can get adaptor mounts to take the saloon OD, The speedo drive ratio is 3.5:1 reduction as opposed to the 2.5:1 of the TR box. a bit more of a difference than would be needed for 14" wheels. The saloon clutch is a diaphram type, & has a different release bearing, so can't properly be used on the orignal TR clutch cover. Better to re-drill the flywheel to take a diaphram cover.

Bob

[badhuis]

On 12/18/2023 at 9:10 AM, rcreweread said:

Also the speedo drive is for 14" wheels, so the speedo will be inaccurate.

Saloons all have 13" wheels as far as I know (owned a 2000 Mk1 & Mk2, 2500 Mk2). Maybe the last 2500S with the alloys have 14"? Not sure about those wheels. 

[BlueTR3A-5EKT]

1 hour ago, badhuis said:

Saloons all have 13" wheels as far as I know (owned a 2000 Mk1 & Mk2, 2500 Mk2). Maybe the last 2500S with the alloys have 14"? Not sure about those wheels. 

Yes the alloys on 2500s are 14 “ same as Stag

[Chris59]

2000 A type overdrive is weaker, 2500 is similar to TR (8 pressure springs).

If your sedan overdrive gearbox is a J type, it's rather easy to adapt to a TR4.

Edited December 19, 2023 by Chris59

[BlueTR3A-5EKT]

On 12/18/2023 at 2:49 AM, Malbaby said:

I have a TR4 4 speed gearbox and a 2500 sedan overdrive gearbox in my garage.

The input shaft diameters are different....enlightenment please.

Order a printed copy of the Moss Europe TR5/6 parts catalogue.
  It contains all the info you need to make these fit a TR.  

Pete Cox wrote that article and it covers all eventualities.  

[badhuis]

On 12/20/2023 at 1:00 PM, BlueTR3A-5EKT said:

Order a printed copy of the Moss Europe TR5/6 parts catalogue.
  It contains all the info you need to make these fit a TR.  

Pete Cox wrote that article and it covers all eventualities.  

PDFs online for these: 

https://www.moss-europe.co.uk/media/pdf/TR2CAT.pdf (page 35)

https://www.moss-europe.co.uk/media/pdf/TR5CAT.pdf (page 36 & 54)

[Malbaby]

Thanks guys.