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Gearbox/clutch Identification


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Hi all,

 

I need to replace the clutch release bearing and carrier on my 4A. I think I have a Triumph 2000 gearbox with J type OD but would like confirmation. This was fitted about 20 years ago by the previous owner.

 

The detent balls & springs in top cover are (or were) held by the press-in caps, not threaded grub screws.

 

The clutch release fork has the two slipper pads to hold the bearing carrier and the carrier ID is 42mm and bearing OD is 77mm. I have another gearbox which may be a 4A box with A type OD where the carrier ID is larger at 52mm ID with the bearing OD at 85mm.

 

Any help appreciated as I would like to order the correct parts first time if possible!

 

Bryan

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Late last night I found the references to the numbers in Roger Williams book - but I can't find any numbers on my gearbox that correspond to the codes.

 

I must have mis-measured last night and the carrier ID is 34mm with bearing ID of 39 and OD of 68 - which seems to correspond to the GRB209 release bearing.

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Does it have a reversing light switch on the Left hand side ? if not then it is not a saloon box.

Also only one overdrive isolator switch (or position for switch) on a saloon.

 

(I have a saloon box in my TR3)

 

Bob.

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Saloon origin gearboxes will have a smaller diameter input shaft than a TR box. Release bearings are smaller diameter. Clutch covers have longer release "fingers", but fit the 4a flywheel. Top cover may not be relied upon for identification. The saloon box with A type overdrive fitted to my TR4 has a much earlier top cover with a dipstick in it!

 

Regards

Nick

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Thanks guys - that's helpful. No reversing light switch on top cover - just a blanking plug on RH end of the interlink mechanism. The release bearing and input shaft is smaller than the other gearbox I have - although no sure of its origin anyway!

 

Are there just the two sizes of input shaft and release bearing out there?

 

Cheers

 

Bryan

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Gearbox number is usually on the lug where the clutch cross shaft goes through...

IIRC, there's just the two sizes, smaller for saloons, but the bigger bearing differs to suit coil spring clutches of early cars ( a flat face), or the later 4a on diaphragm spring clutches (with a rounded face).

 

Nick

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Thanks - I think that's sorted it. My box seems to be from a saloon with the smaller input shaft and bearing, with the clutch cover with the longer fingers to match the smaller bearing. The other box would seem to be a later TR box with the rounded release bearing face to mate with a diaphragm clutch - larger diam input shaft and bearing.

 

A bit more TR knowledge learnt this week.

 

Thanks

 

Bryan

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