Monty79SWB said:

Over the last couple of years I've rebuilt my S3 gearbox (suffix A) lots of new 'decent' parts lots of time no hurry double checking everything. Got it fitted and all works well except for second gear. When engaged in 2nd gear it has what is best described as a 'winding sound'. I works, but there is this loudish noise. All the other gears are fine it's just in second. Only done a mile and not I've pushed it. I've checked the part numbers of the new parts fitted which are correct for Suffix A.
The first second Syncro was replaced with a new (Genuine) part which has 31 outer teeth as per the part removed.

I've just removed the box (again - even more fun in the rain). Any suggestions what I should be looking for when I take it apart?

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jamesmartin said:

youd need to count the teeth on 2nd gear plus corresponding teeth on l/s

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Monty79SWB said:

Will do, it was a second hand gearbox that I refurbished, so I'm guessing it was OK but who knows. Thanks for that. One thing I am noticing is the photo's of the 1/2 syncro on different supplier web-site for the suffix A unit show the internal 'piece' wrong way around in some of the photos (about 25%of them) The photo below I hope is the WRONG way around - I think. The second photo I think is correct.


.View attachment 223057

View attachment 223058

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Blackburn said:

Was the layshaft renewed?
If not the noise could be the new part is not making full contact with worn old part usually takes awhile before they run well together.

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jamesmartin said:

2nd pic is correct,also check rev idler isnt catching synchro hub when 2nds engaged

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Blackburn said:

Was the layshaft renewed?
If not the noise could be the new part is not making full contact with worn old part usually takes awhile before they run well together.

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Monty79SWB said:

But the Syncro is also engaged with the lay shaft with the same teeth in first with no noise (or am I missing something)

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jamesmartin said:

synchro hub never engages with the l/s ,the outer teeth engage with rev idler[/QU

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Monty79SWB said:

Both of which were renewed !!

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jamesmartin said:

remove top rev in neutral engage 2nd have a look at rev idler, if ok count the teeth if ok might just be a poor gear in which case a close look at the polishing on teeth will show good or poor mesh of teeth

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Monty79SWB said:

Thanks for all the replies. I THINK I have found the problem, if so annoyingly, I could have sorted it in situ but at least I didn't take the box apart only removed the top cover.

With the top cover removed I turned the shaft with second gear engaged, and there was the noise.

I noticed that the reverse gear was sometimes catching very very slightly on the 1/2 syncro's gear. Moving the selector just half a millimetre forward (towards the engine) it didn't do it. The reverse selector fork appears to be non original and not to pull the reverse idler far enough forward out of the way.

This is a suffix A box that I have rebuild (never saw it running) so I took the reverse selector (original part number on it FRC1815) from my old Suffix B box and that seems to work fine and it moves the reverse idler well clear - no noise so the obvious answer seems to be that the selector fork is just wrong.

The LR parts catalogue shows the FRC1815 for Suffix B boxes onwards but it looks to work fine, does anyone have any reason that I should not use it in my rebuilt Suffix A box?

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jamesmartin said:

its because suffix a uses a different rev idler, in neutral rev idler should be right forward against the casing,if its working then whilst not right it would be ok,theres some adjustment on all forks

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pef77 said:

There are a few good you tube videos of gearbox rebuilds " steam wally " is one of them he found that a 1st - 2nd synchro had been supplied with the inside reversed.. the other is "Geoffrey croker" I think.. good videos and informative, helped me do mine..

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