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Can D-type O/D bolt onto 1500 non O/D box?


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Nick_Jones wrote:
Short answer: no.
Longer answer: still no


You need to brush up on your people skills Nick :P


Want to look onto my 3 rail d-type box as it making a little noise whilst driving.
Anyone know what I might fondbthat would explain the noise?


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Richard_B wrote:


Even longer answer: Yes,  but, only after you have stripped it down and replaced the mainshaft with an O/D mainshaft.  

It's worse than that.  With single rail box the gear change remote attaches to lugs on the J-type OD casting.  These are not even present on all J type castings (Guess how I know that!!) and were NEVER present on D type castings.  So yes, you could transfer all the internals and D type from the 3 rail (though goodness knows why you'd want to) but you still wouldn't be able to change gear.....

Alternatively, you could buy a special big-tip D type OD mainshaft (IF they even exist) and use the single rail components to build up an OD box in the 3 rail casing...... maybe.

Easier (and probably more accurate) to just say NO!  

"People skills need brushing up"...... ya cheeky monkey!  :P


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Thanks fellas.

I am sure your people skills are fine when talking to people and not typing to them Nick ;)

My 3 rail box just seems to be making some type of noise like a scraping noise which makes me thing 'release bearing' as has been said.
But i am noticing a smell that smells a little like waxoyl and that doesnt sound like release bearing.

Bit disapointed really as all the bench tests on this box were fine and O/D works fine. I am tempted to bite the bullet and buy a j-type box but dont want to fall foul of this type of thing with another box, which is quite possible.

This leads me to thought of buying a rebuild kit for 3 rail O/D box from paddocks or the like and just rebuild the damb thing.
I am pretty good with mechanicals but never rebuilt one of these boxes before... How difficult is it to strip out and rebuild? :-/

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Noises are often layshaft pins. This is from a local who has built a few.......
And new pins are "variable" in quality. Record for one was under 3 miles, it had no hardening. Supplier gave a refund for the part cost. Since then he only uses good used pins, though they are getting harder to find.
Long and short, good non-od boxes are very useful as sources of spares. Often cheap as chips, and way better than using new bits. Not sure about synchros now, but again new ones were horrific.
Long and short, don't assume a rebuild kit will solve the issues. Strip and check what is required first, before fitting a whole load of  parts of unknown origin....

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Today i stripped out the seats and gearbox cover and removed rhe gearbox.

The oil that was only installed a few months ago, was metalic upon draining.
What I found was
1) roller bearing housing split in half.
2) mainshaft tip has serious wear where roller bearings contact.
3) roller bearings worn to match wear on mainshaft tip (like a stretched teardrop).
4) sincro face wear at 4th gear.
5) Bush wear on central rail.

Layshaft seams ok

Will post pick of mainshaft tip wear for feedback as replcemwnt shaft may make rebuild pointless costwise unless i can pick up a cheap d-type mainshaft!!

Here we go again

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Pic is fine..... but shows bad things  :(

That is a very common failure point.  Mainshaft is scrap IMO.  There are those who either grind them down and sleeve them (risk of outright breakage due to reduced size) or even bore out and fit an insert (either insert not hard enough and wears quickly or just comes loose).  Would not want that myself.

The 4th gear synchro wear is caused by the excess movement resulting from the knackered bearing.


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I would say that is even harder to do properly than the two "repairs" mentioned above.  Probably worth giving Dave at Canleys a ring to see if new shafts are available.  Trouble with buying more gearboxes is that quite a high proportion will be like the one you have!

You also need to look inside the input shaft where the needle roller bearing runs.  The originals would have run directly on a ground surface and are lubricated by oil holes drilled from outside.  However, once this surface gets worn/chewed they are often replaced with a drawn-cup ("Torrington") type roller pack - this seems to be what you were describing earlier?  These don't usually last very long - mostly because they loose the extra lubrication from the oil holes which are blocked by the outer casing.


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The Torrington bearing was standard in the early boxes and, as said, this is not a surprising result from running small diameter, un-caged rollers on a shaft with lateral loadings, which, by design, must apply uneven loading over the length of the rollers. (Hence I change to bronze bushes. Not to the liking of many, if any, members on this forum)
The uneven loading causes the rollers to not run parallel to the shaft centre, imparting a degree of skidding and the angle causes loading on the tips and centres of the rollers.

The amount of wear on that tip makes a repair unlikely.
Some may weld, metal spray or sleeve, but risky.  

For my own, personal use, I would apply a sleeve at red heat, whilst rotating in a lathe and peining it to comply, to get a good solid shrink fit. ( this is rather a busy procedure, using a torch and hammer at the same time whilst working on a lathe)
Next machine it and use a bush.
Have only ever done this once for another person's car, an MGB. They have a larger tip, but this one had had a sleeve fitted by someone which had moved and really caused some mischief.
I would not do this to a Spit box for someone else or recommend that it be done.  Result depends on how well it is done and we are all capable of making blunders.

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peterhlewis wrote:
OD mainshaft is tkc923,   unless you upgrade to a mainshaft 18mm spigot this typical failure will return again in the future

bear in mind this design started with the standard eight and it the weak point .

Mike Paporth can supply mainshaft and stem gears with the big spigot


Hi Pete

Thanks for the info mate.

Gears look ok. Do stem gears require replacing to accomodate the bigger 18mm dia of HD mainshaft?

I am selling this car and just dont want to sell with any problems hence the possible rebuild. As such I dont want to go to the added expense of a heavy duty mainshaft at £200 a pop plus £100 for rebuild kit!

A standard rebuild (original part mainshaft) will be sufficient unless I find a suitable alternative box.

Cheers matey

But if I was keeping, I would def use HD mainshaft with 18mm

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